{
  "language": "Solidity",
  "sources": {
    "contracts/Ouroborus.sol": {
      "content": "//https://medium.com/@mythicmessiah/the-myth-of-ouroborosu-ouroborous-402f6e29e1c1\r\n\r\n\r\n// SPDX-License-Identifier: MIT\r\npragma solidity ^0.8.10;\r\npragma experimental ABIEncoderV2;\r\n\r\n////// lib/openzeppelin-contracts/contracts/utils/Context.sol\r\n// OpenZeppelin Contracts v4.4.0 (utils/Context.sol)\r\n\r\n/* pragma solidity ^0.8.0; */\r\n\r\n/**\r\n * @dev Provides information about the current execution context, including the\r\n * sender of the transaction and its data. While these are generally available\r\n * via msg.sender and msg.data, they should not be accessed in such a direct\r\n * manner, since when dealing with meta-transactions the account sending and\r\n * paying for execution may not be the actual sender (as far as an application\r\n * is concerned).\r\n *\r\n * This contract is only required for intermediate, library-like contracts.\r\n */\r\nabstract contract Context {\r\n    function _msgSender() internal view virtual returns (address) {\r\n        return msg.sender;\r\n    }\r\n\r\n    function _msgData() internal view virtual returns (bytes calldata) {\r\n        return msg.data;\r\n    }\r\n}\r\n\r\n////// lib/openzeppelin-contracts/contracts/access/Ownable.sol\r\n// OpenZeppelin Contracts v4.4.0 (access/Ownable.sol)\r\n\r\n/* pragma solidity ^0.8.0; */\r\n\r\n/* import \"../utils/Context.sol\"; */\r\n\r\n/**\r\n * @dev Contract module which provides a basic access control mechanism, where\r\n * there is an account (an owner) that can be granted exclusive access to\r\n * specific functions.\r\n *\r\n * By default, the owner account will be the one that deploys the contract. This\r\n * can later be changed with {transferOwnership}.\r\n *\r\n * This module is used through inheritance. It will make available the modifier\r\n * `onlyOwner`, which can be applied to your functions to restrict their use to\r\n * the owner.\r\n */\r\nabstract contract Ownable is Context {\r\n    address private _owner;\r\n\r\n    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);\r\n\r\n    /**\r\n     * @dev Initializes the contract setting the deployer as the initial owner.\r\n     */\r\n    constructor() {\r\n        _transferOwnership(_msgSender());\r\n    }\r\n\r\n    /**\r\n     * @dev Returns the address of the current owner.\r\n     */\r\n    function owner() public view virtual returns (address) {\r\n        return _owner;\r\n    }\r\n\r\n    /**\r\n     * @dev Throws if called by any account other than the owner.\r\n     */\r\n    modifier onlyOwner() {\r\n        require(owner() == _msgSender(), \"Ownable: caller is not the owner\");\r\n        _;\r\n    }\r\n\r\n    /**\r\n     * @dev Leaves the contract without owner. It will not be possible to call\r\n     * `onlyOwner` functions anymore. Can only be called by the current owner.\r\n     *\r\n     * NOTE: Renouncing ownership will leave the contract without an owner,\r\n     * thereby removing any functionality that is only available to the owner.\r\n     */\r\n    function renounceOwnership() public virtual onlyOwner {\r\n        _transferOwnership(address(0));\r\n    }\r\n\r\n    /**\r\n     * @dev Transfers ownership of the contract to a new account (`newOwner`).\r\n     * Can only be called by the current owner.\r\n     */\r\n    function transferOwnership(address newOwner) public virtual onlyOwner {\r\n        require(newOwner != address(0), \"Ownable: new owner is the zero address\");\r\n        _transferOwnership(newOwner);\r\n    }\r\n\r\n    /**\r\n     * @dev Transfers ownership of the contract to a new account (`newOwner`).\r\n     * Internal function without access restriction.\r\n     */\r\n    function _transferOwnership(address newOwner) internal virtual {\r\n        address oldOwner = _owner;\r\n        _owner = newOwner;\r\n        emit OwnershipTransferred(oldOwner, newOwner);\r\n    }\r\n}\r\n\r\n////// lib/openzeppelin-contracts/contracts/token/ERC20/IERC20.sol\r\n// OpenZeppelin Contracts v4.4.0 (token/ERC20/IERC20.sol)\r\n\r\n/* pragma solidity ^0.8.0; */\r\n\r\n/**\r\n * @dev Interface of the ERC20 standard as defined in the EIP.\r\n */\r\ninterface IERC20 {\r\n    /**\r\n     * @dev Returns the amount of tokens in existence.\r\n     */\r\n    function totalSupply() external view returns (uint256);\r\n\r\n    /**\r\n     * @dev Returns the amount of tokens owned by `account`.\r\n     */\r\n    function balanceOf(address account) external view returns (uint256);\r\n\r\n    /**\r\n     * @dev Moves `amount` tokens from the caller's account to `recipient`.\r\n     *\r\n     * Returns a boolean value indicating whether the operation succeeded.\r\n     *\r\n     * Emits a {Transfer} event.\r\n     */\r\n    function transfer(address recipient, uint256 amount) external returns (bool);\r\n\r\n    /**\r\n     * @dev Returns the remaining number of tokens that `spender` will be\r\n     * allowed to spend on behalf of `owner` through {transferFrom}. This is\r\n     * zero by default.\r\n     *\r\n     * This value changes when {approve} or {transferFrom} are called.\r\n     */\r\n    function allowance(address owner, address spender) external view returns (uint256);\r\n\r\n    /**\r\n     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.\r\n     *\r\n     * Returns a boolean value indicating whether the operation succeeded.\r\n     *\r\n     * IMPORTANT: Beware that changing an allowance with this method brings the risk\r\n     * that someone may use both the old and the new allowance by unfortunate\r\n     * transaction ordering. One possible solution to mitigate this race\r\n     * condition is to first reduce the spender's allowance to 0 and set the\r\n     * desired value afterwards:\r\n     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729\r\n     *\r\n     * Emits an {Approval} event.\r\n     */\r\n    function approve(address spender, uint256 amount) external returns (bool);\r\n\r\n    /**\r\n     * @dev Moves `amount` tokens from `sender` to `recipient` using the\r\n     * allowance mechanism. `amount` is then deducted from the caller's\r\n     * allowance.\r\n     *\r\n     * Returns a boolean value indicating whether the operation succeeded.\r\n     *\r\n     * Emits a {Transfer} event.\r\n     */\r\n    function transferFrom(\r\n        address sender,\r\n        address recipient,\r\n        uint256 amount\r\n    ) external returns (bool);\r\n\r\n    /**\r\n     * @dev Emitted when `value` tokens are moved from one account (`from`) to\r\n     * another (`to`).\r\n     *\r\n     * Note that `value` may be zero.\r\n     */\r\n    event Transfer(address indexed from, address indexed to, uint256 value);\r\n\r\n    /**\r\n     * @dev Emitted when the allowance of a `spender` for an `owner` is set by\r\n     * a call to {approve}. `value` is the new allowance.\r\n     */\r\n    event Approval(address indexed owner, address indexed spender, uint256 value);\r\n}\r\n\r\n////// lib/openzeppelin-contracts/contracts/token/ERC20/extensions/IERC20Metadata.sol\r\n// OpenZeppelin Contracts v4.4.0 (token/ERC20/extensions/IERC20Metadata.sol)\r\n\r\n/* pragma solidity ^0.8.0; */\r\n\r\n/* import \"../IERC20.sol\"; */\r\n\r\n/**\r\n * @dev Interface for the optional metadata functions from the ERC20 standard.\r\n *\r\n * _Available since v4.1._\r\n */\r\ninterface IERC20Metadata is IERC20 {\r\n    /**\r\n     * @dev Returns the name of the token.\r\n     */\r\n    function name() external view returns (string memory);\r\n\r\n    /**\r\n     * @dev Returns the symbol of the token.\r\n     */\r\n    function symbol() external view returns (string memory);\r\n\r\n    /**\r\n     * @dev Returns the decimals places of the token.\r\n     */\r\n    function decimals() external view returns (uint8);\r\n}\r\n\r\n////// lib/openzeppelin-contracts/contracts/token/ERC20/ERC20.sol\r\n// OpenZeppelin Contracts v4.4.0 (token/ERC20/ERC20.sol)\r\n\r\n/* pragma solidity ^0.8.0; */\r\n\r\n/* import \"./IERC20.sol\"; */\r\n/* import \"./extensions/IERC20Metadata.sol\"; */\r\n/* import \"../../utils/Context.sol\"; */\r\n\r\n/**\r\n * @dev Implementation of the {IERC20} interface.\r\n *\r\n * This implementation is agnostic to the way tokens are created. This means\r\n * that a supply mechanism has to be added in a derived contract using {_mint}.\r\n * For a generic mechanism see {ERC20PresetMinterPauser}.\r\n *\r\n * TIP: For a detailed writeup see our guide\r\n * https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How\r\n * to implement supply mechanisms].\r\n *\r\n * We have followed general OpenZeppelin Contracts guidelines: functions revert\r\n * instead returning `false` on failure. This behavior is nonetheless\r\n * conventional and does not conflict with the expectations of ERC20\r\n * applications.\r\n *\r\n * Additionally, an {Approval} event is emitted on calls to {transferFrom}.\r\n * This allows applications to reconstruct the allowance for all accounts just\r\n * by listening to said events. Other implementations of the EIP may not emit\r\n * these events, as it isn't required by the specification.\r\n *\r\n * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}\r\n * functions have been added to mitigate the well-known issues around setting\r\n * allowances. See {IERC20-approve}.\r\n */\r\ncontract ERC20 is Context, IERC20, IERC20Metadata {\r\n    mapping(address => uint256) private _balances;\r\n\r\n    mapping(address => mapping(address => uint256)) private _allowances;\r\n\r\n    uint256 private _totalSupply;\r\n\r\n    string private _name;\r\n    string private _symbol;\r\n\r\n    /**\r\n     * @dev Sets the values for {name} and {symbol}.\r\n     *\r\n     * The default value of {decimals} is 18. To select a different value for\r\n     * {decimals} you should overload it.\r\n     *\r\n     * All two of these values are immutable: they can only be set once during\r\n     * construction.\r\n     */\r\n    constructor(string memory name_, string memory symbol_) {\r\n        _name = name_;\r\n        _symbol = symbol_;\r\n    }\r\n\r\n    /**\r\n     * @dev Returns the name of the token.\r\n     */\r\n    function name() public view virtual override returns (string memory) {\r\n        return _name;\r\n    }\r\n\r\n    /**\r\n     * @dev Returns the symbol of the token, usually a shorter version of the\r\n     * name.\r\n     */\r\n    function symbol() public view virtual override returns (string memory) {\r\n        return _symbol;\r\n    }\r\n\r\n    /**\r\n     * @dev Returns the number of decimals used to get its user representation.\r\n     * For example, if `decimals` equals `2`, a balance of `505` tokens should\r\n     * be displayed to a user as `5.05` (`505 / 10 ** 2`).\r\n     *\r\n     * Tokens usually opt for a value of 18, imitating the relationship between\r\n     * Ether and Wei. This is the value {ERC20} uses, unless this function is\r\n     * overridden;\r\n     *\r\n     * NOTE: This information is only used for _display_ purposes: it in\r\n     * no way affects any of the arithmetic of the contract, including\r\n     * {IERC20-balanceOf} and {IERC20-transfer}.\r\n     */\r\n    function decimals() public view virtual override returns (uint8) {\r\n        return 18;\r\n    }\r\n\r\n    /**\r\n     * @dev See {IERC20-totalSupply}.\r\n     */\r\n    function totalSupply() public view virtual override returns (uint256) {\r\n        return _totalSupply;\r\n    }\r\n\r\n    /**\r\n     * @dev See {IERC20-balanceOf}.\r\n     */\r\n    function balanceOf(address account) public view virtual override returns (uint256) {\r\n        return _balances[account];\r\n    }\r\n\r\n    /**\r\n     * @dev See {IERC20-transfer}.\r\n     *\r\n     * Requirements:\r\n     *\r\n     * - `recipient` cannot be the zero address.\r\n     * - the caller must have a balance of at least `amount`.\r\n     */\r\n    function transfer(address recipient, uint256 amount) public virtual override returns (bool) {\r\n        _transfer(_msgSender(), recipient, amount);\r\n        return true;\r\n    }\r\n\r\n    /**\r\n     * @dev See {IERC20-allowance}.\r\n     */\r\n    function allowance(address owner, address spender) public view virtual override returns (uint256) {\r\n        return _allowances[owner][spender];\r\n    }\r\n\r\n    /**\r\n     * @dev See {IERC20-approve}.\r\n     *\r\n     * Requirements:\r\n     *\r\n     * - `spender` cannot be the zero address.\r\n     */\r\n    function approve(address spender, uint256 amount) public virtual override returns (bool) {\r\n        _approve(_msgSender(), spender, amount);\r\n        return true;\r\n    }\r\n\r\n    /**\r\n     * @dev See {IERC20-transferFrom}.\r\n     *\r\n     * Emits an {Approval} event indicating the updated allowance. This is not\r\n     * required by the EIP. See the note at the beginning of {ERC20}.\r\n     *\r\n     * Requirements:\r\n     *\r\n     * - `sender` and `recipient` cannot be the zero address.\r\n     * - `sender` must have a balance of at least `amount`.\r\n     * - the caller must have allowance for ``sender``'s tokens of at least\r\n     * `amount`.\r\n     */\r\n    function transferFrom(\r\n        address sender,\r\n        address recipient,\r\n        uint256 amount\r\n    ) public virtual override returns (bool) {\r\n        _transfer(sender, recipient, amount);\r\n\r\n        uint256 currentAllowance = _allowances[sender][_msgSender()];\r\n        require(currentAllowance >= amount, \"ERC20: transfer amount exceeds allowance\");\r\n        unchecked {\r\n            _approve(sender, _msgSender(), currentAllowance - amount);\r\n        }\r\n\r\n        return true;\r\n    }\r\n\r\n    /**\r\n     * @dev Moves `amount` of tokens from `sender` to `recipient`.\r\n     *\r\n     * This internal function is equivalent to {transfer}, and can be used to\r\n     * e.g. implement automatic token fees, slashing mechanisms, etc.\r\n     *\r\n     * Emits a {Transfer} event.\r\n     *\r\n     * Requirements:\r\n     *\r\n     * - `sender` cannot be the zero address.\r\n     * - `recipient` cannot be the zero address.\r\n     * - `sender` must have a balance of at least `amount`.\r\n     */\r\n    function _transfer(\r\n        address sender,\r\n        address recipient,\r\n        uint256 amount\r\n    ) internal virtual {\r\n        require(sender != address(0), \"ERC20: transfer from the zero address\");\r\n        require(recipient != address(0), \"ERC20: transfer to the zero address\");\r\n\r\n        _beforeTokenTransfer(sender, recipient, amount);\r\n\r\n        uint256 senderBalance = _balances[sender];\r\n        require(senderBalance >= amount, \"ERC20: transfer amount exceeds balance\");\r\n        unchecked {\r\n            _balances[sender] = senderBalance - amount;\r\n        }\r\n        _balances[recipient] += amount;\r\n\r\n        emit Transfer(sender, recipient, amount);\r\n\r\n        _afterTokenTransfer(sender, recipient, amount);\r\n    }\r\n\r\n    /** @dev Creates `amount` tokens and assigns them to `account`, increasing\r\n     * the total supply.\r\n     *\r\n     * Emits a {Transfer} event with `from` set to the zero address.\r\n     *\r\n     * Requirements:\r\n     *\r\n     * - `account` cannot be the zero address.\r\n     */\r\n    function _mint(address account, uint256 amount) internal virtual {\r\n        require(account != address(0), \"ERC20: mint to the zero address\");\r\n\r\n        _beforeTokenTransfer(address(0), account, amount);\r\n\r\n        _totalSupply += amount;\r\n        _balances[account] += amount;\r\n        emit Transfer(address(0), account, amount);\r\n\r\n        _afterTokenTransfer(address(0), account, amount);\r\n    }\r\n\r\n\r\n    /**\r\n     * @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.\r\n     *\r\n     * This internal function is equivalent to `approve`, and can be used to\r\n     * e.g. set automatic allowances for certain subsystems, etc.\r\n     *\r\n     * Emits an {Approval} event.\r\n     *\r\n     * Requirements:\r\n     *\r\n     * - `owner` cannot be the zero address.\r\n     * - `spender` cannot be the zero address.\r\n     */\r\n    function _approve(\r\n        address owner,\r\n        address spender,\r\n        uint256 amount\r\n    ) internal virtual {\r\n        require(owner != address(0), \"ERC20: approve from the zero address\");\r\n        require(spender != address(0), \"ERC20: approve to the zero address\");\r\n\r\n        _allowances[owner][spender] = amount;\r\n        emit Approval(owner, spender, amount);\r\n    }\r\n\r\n    /**\r\n     * @dev Hook that is called before any transfer of tokens. This includes\r\n     * minting and burning.\r\n     *\r\n     * Calling conditions:\r\n     *\r\n     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens\r\n     * will be transferred to `to`.\r\n     * - when `from` is zero, `amount` tokens will be minted for `to`.\r\n     * - when `to` is zero, `amount` of ``from``'s tokens will be burned.\r\n     * - `from` and `to` are never both zero.\r\n     *\r\n     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].\r\n     */\r\n    function _beforeTokenTransfer(\r\n        address from,\r\n        address to,\r\n        uint256 amount\r\n    ) internal virtual {}\r\n\r\n    /**\r\n     * @dev Hook that is called after any transfer of tokens. This includes\r\n     * minting and burning.\r\n     *\r\n     * Calling conditions:\r\n     *\r\n     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens\r\n     * has been transferred to `to`.\r\n     * - when `from` is zero, `amount` tokens have been minted for `to`.\r\n     * - when `to` is zero, `amount` of ``from``'s tokens have been burned.\r\n     * - `from` and `to` are never both zero.\r\n     *\r\n     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].\r\n     */\r\n    function _afterTokenTransfer(\r\n        address from,\r\n        address to,\r\n        uint256 amount\r\n    ) internal virtual {}\r\n}\r\n\r\n////// lib/openzeppelin-contracts/contracts/utils/math/SafeMath.sol\r\n// OpenZeppelin Contracts v4.4.0 (utils/math/SafeMath.sol)\r\n\r\n/* pragma solidity ^0.8.0; */\r\n\r\n// CAUTION\r\n// This version of SafeMath should only be used with Solidity 0.8 or later,\r\n// because it relies on the compiler's built in overflow checks.\r\n\r\n/**\r\n * @dev Wrappers over Solidity's arithmetic operations.\r\n *\r\n * NOTE: `SafeMath` is generally not needed starting with Solidity 0.8, since the compiler\r\n * now has built in overflow checking.\r\n */\r\nlibrary SafeMath {\r\n    /**\r\n     * @dev Returns the addition of two unsigned integers, with an overflow flag.\r\n     *\r\n     * _Available since v3.4._\r\n     */\r\n    function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {\r\n        unchecked {\r\n            uint256 c = a + b;\r\n            if (c < a) return (false, 0);\r\n            return (true, c);\r\n        }\r\n    }\r\n\r\n    /**\r\n     * @dev Returns the substraction of two unsigned integers, with an overflow flag.\r\n     *\r\n     * _Available since v3.4._\r\n     */\r\n    function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {\r\n        unchecked {\r\n            if (b > a) return (false, 0);\r\n            return (true, a - b);\r\n        }\r\n    }\r\n\r\n    /**\r\n     * @dev Returns the multiplication of two unsigned integers, with an overflow flag.\r\n     *\r\n     * _Available since v3.4._\r\n     */\r\n    function tryMul(uint256 a, uint256 b) internal pure returns (bool, uint256) {\r\n        unchecked {\r\n            // Gas optimization: this is cheaper than requiring 'a' not being zero, but the\r\n            // benefit is lost if 'b' is also tested.\r\n            // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522\r\n            if (a == 0) return (true, 0);\r\n            uint256 c = a * b;\r\n            if (c / a != b) return (false, 0);\r\n            return (true, c);\r\n        }\r\n    }\r\n\r\n    /**\r\n     * @dev Returns the division of two unsigned integers, with a division by zero flag.\r\n     *\r\n     * _Available since v3.4._\r\n     */\r\n    function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {\r\n        unchecked {\r\n            if (b == 0) return (false, 0);\r\n            return (true, a / b);\r\n        }\r\n    }\r\n\r\n    /**\r\n     * @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.\r\n     *\r\n     * _Available since v3.4._\r\n     */\r\n    function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {\r\n        unchecked {\r\n            if (b == 0) return (false, 0);\r\n            return (true, a % b);\r\n        }\r\n    }\r\n\r\n    /**\r\n     * @dev Returns the addition of two unsigned integers, reverting on\r\n     * overflow.\r\n     *\r\n     * Counterpart to Solidity's `+` operator.\r\n     *\r\n     * Requirements:\r\n     *\r\n     * - Addition cannot overflow.\r\n     */\r\n    function add(uint256 a, uint256 b) internal pure returns (uint256) {\r\n        return a + b;\r\n    }\r\n\r\n    /**\r\n     * @dev Returns the subtraction of two unsigned integers, reverting on\r\n     * overflow (when the result is negative).\r\n     *\r\n     * Counterpart to Solidity's `-` operator.\r\n     *\r\n     * Requirements:\r\n     *\r\n     * - Subtraction cannot overflow.\r\n     */\r\n    function sub(uint256 a, uint256 b) internal pure returns (uint256) {\r\n        return a - b;\r\n    }\r\n\r\n    /**\r\n     * @dev Returns the multiplication of two unsigned integers, reverting on\r\n     * overflow.\r\n     *\r\n     * Counterpart to Solidity's `*` operator.\r\n     *\r\n     * Requirements:\r\n     *\r\n     * - Multiplication cannot overflow.\r\n     */\r\n    function mul(uint256 a, uint256 b) internal pure returns (uint256) {\r\n        return a * b;\r\n    }\r\n\r\n    /**\r\n     * @dev Returns the integer division of two unsigned integers, reverting on\r\n     * division by zero. The result is rounded towards zero.\r\n     *\r\n     * Counterpart to Solidity's `/` operator.\r\n     *\r\n     * Requirements:\r\n     *\r\n     * - The divisor cannot be zero.\r\n     */\r\n    function div(uint256 a, uint256 b) internal pure returns (uint256) {\r\n        return a / b;\r\n    }\r\n\r\n    /**\r\n     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),\r\n     * reverting when dividing by zero.\r\n     *\r\n     * Counterpart to Solidity's `%` operator. This function uses a `revert`\r\n     * opcode (which leaves remaining gas untouched) while Solidity uses an\r\n     * invalid opcode to revert (consuming all remaining gas).\r\n     *\r\n     * Requirements:\r\n     *\r\n     * - The divisor cannot be zero.\r\n     */\r\n    function mod(uint256 a, uint256 b) internal pure returns (uint256) {\r\n        return a % b;\r\n    }\r\n\r\n    /**\r\n     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on\r\n     * overflow (when the result is negative).\r\n     *\r\n     * CAUTION: This function is deprecated because it requires allocating memory for the error\r\n     * message unnecessarily. For custom revert reasons use {trySub}.\r\n     *\r\n     * Counterpart to Solidity's `-` operator.\r\n     *\r\n     * Requirements:\r\n     *\r\n     * - Subtraction cannot overflow.\r\n     */\r\n    function sub(\r\n        uint256 a,\r\n        uint256 b,\r\n        string memory errorMessage\r\n    ) internal pure returns (uint256) {\r\n        unchecked {\r\n            require(b <= a, errorMessage);\r\n            return a - b;\r\n        }\r\n    }\r\n\r\n    /**\r\n     * @dev Returns the integer division of two unsigned integers, reverting with custom message on\r\n     * division by zero. The result is rounded towards zero.\r\n     *\r\n     * Counterpart to Solidity's `/` operator. Note: this function uses a\r\n     * `revert` opcode (which leaves remaining gas untouched) while Solidity\r\n     * uses an invalid opcode to revert (consuming all remaining gas).\r\n     *\r\n     * Requirements:\r\n     *\r\n     * - The divisor cannot be zero.\r\n     */\r\n    function div(\r\n        uint256 a,\r\n        uint256 b,\r\n        string memory errorMessage\r\n    ) internal pure returns (uint256) {\r\n        unchecked {\r\n            require(b > 0, errorMessage);\r\n            return a / b;\r\n        }\r\n    }\r\n\r\n    /**\r\n     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),\r\n     * reverting with custom message when dividing by zero.\r\n     *\r\n     * CAUTION: This function is deprecated because it requires allocating memory for the error\r\n     * message unnecessarily. For custom revert reasons use {tryMod}.\r\n     *\r\n     * Counterpart to Solidity's `%` operator. This function uses a `revert`\r\n     * opcode (which leaves remaining gas untouched) while Solidity uses an\r\n     * invalid opcode to revert (consuming all remaining gas).\r\n     *\r\n     * Requirements:\r\n     *\r\n     * - The divisor cannot be zero.\r\n     */\r\n    function mod(\r\n        uint256 a,\r\n        uint256 b,\r\n        string memory errorMessage\r\n    ) internal pure returns (uint256) {\r\n        unchecked {\r\n            require(b > 0, errorMessage);\r\n            return a % b;\r\n        }\r\n    }\r\n}\r\n\r\ninterface IUniswapV2Factory {\r\n    event PairCreated(\r\n        address indexed token0,\r\n        address indexed token1,\r\n        address pair,\r\n        uint256\r\n    );\r\n\r\n    function createPair(address tokenA, address tokenB)\r\n        external\r\n        returns (address pair);\r\n}\r\n\r\ninterface IUniswapV2Router02 {\r\n    function factory() external pure returns (address);\r\n\r\n    function swapExactTokensForTokensSupportingFeeOnTransferTokens(\r\n        uint256 amountIn,\r\n        uint256 amountOutMin,\r\n        address[] calldata path,\r\n        address to,\r\n        uint256 deadline\r\n    ) external;\r\n}\r\n\r\ncontract Ouroboros is ERC20, Ownable {\r\n    using SafeMath for uint256;\r\n\r\n    IUniswapV2Router02 public immutable uniswapV2Router;\r\n    address public immutable uniswapV2Pair;\r\n    address public constant deadAddress = address(0xdead);\r\n    address public USDC = 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48;\r\n\r\n    bool private swapping;\r\n\r\n    address public devWallet;\r\n\r\n    uint256 public maxTransactionAmount;\r\n    uint256 public swapTokensAtAmount;\r\n    uint256 public maxWallet;\r\n\r\n    bool public limitsInEffect = true;\r\n    bool public tradingActive = false;\r\n    bool public swapEnabled = false;\r\n\r\n    uint256 public buyTotalFees;\r\n    uint256 public buyDevFee;\r\n    uint256 public buyLiquidityFee;\r\n\r\n    uint256 public sellTotalFees;\r\n    uint256 public sellDevFee;\r\n    uint256 public sellLiquidityFee;\r\n\r\n    /******************/\r\n\r\n    // exlcude from fees and max transaction amount\r\n    mapping(address => bool) private _isExcludedFromFees;\r\n    mapping(address => bool) public _isExcludedMaxTransactionAmount;\r\n\r\n\r\n    event ExcludeFromFees(address indexed account, bool isExcluded);\r\n\r\n    event devWalletUpdated(\r\n        address indexed newWallet,\r\n        address indexed oldWallet\r\n    );\r\n\r\n    constructor() ERC20(\"The Myth Of Ouroboros\", \"OUROBOROS\") {\r\n        IUniswapV2Router02 _uniswapV2Router = IUniswapV2Router02(\r\n            0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D\r\n        );\r\n\r\n        excludeFromMaxTransaction(address(_uniswapV2Router), true);\r\n        uniswapV2Router = _uniswapV2Router;\r\n\r\n        uniswapV2Pair = IUniswapV2Factory(_uniswapV2Router.factory())\r\n            .createPair(address(this), USDC);\r\n        excludeFromMaxTransaction(address(uniswapV2Pair), true);\r\n\r\n\r\n        uint256 _buyDevFee = 1;\r\n        uint256 _buyLiquidityFee = 1;\r\n\r\n        uint256 _sellDevFee = 1;\r\n        uint256 _sellLiquidityFee = 1;\r\n\r\n        uint256 totalSupply = 100_000_000_000 * 1e18;\r\n\r\n        maxTransactionAmount =  totalSupply * 1 / 100; // 1% from total supply maxTransactionAmountTxn\r\n        maxWallet = totalSupply * 2 / 100; // 2% from total supply maxWallet\r\n        swapTokensAtAmount = (totalSupply * 5) / 10000; // 0.05% swap wallet\r\n\r\n        buyDevFee = _buyDevFee;\r\n        buyLiquidityFee = _buyLiquidityFee;\r\n        buyTotalFees = buyDevFee + buyLiquidityFee;\r\n\r\n        sellDevFee = _sellDevFee;\r\n        sellLiquidityFee = _sellLiquidityFee;\r\n        sellTotalFees = sellDevFee + sellLiquidityFee;\r\n\r\n        devWallet = address(0x13AC487ef93e658df4180f75b9d9582369b9a1Cf); // set as dev wallet\r\n\r\n        // exclude from paying fees or having max transaction amount\r\n        excludeFromFees(owner(), true);\r\n        excludeFromFees(address(this), true);\r\n        excludeFromFees(address(0xdead), true);\r\n\r\n        excludeFromMaxTransaction(owner(), true);\r\n        excludeFromMaxTransaction(address(this), true);\r\n        excludeFromMaxTransaction(address(0xdead), true);\r\n\r\n        /*\r\n            _mint is an internal function in ERC20.sol that is only called here,\r\n            and CANNOT be called ever again\r\n        */\r\n        _mint(msg.sender, totalSupply);\r\n    }\r\n\r\n    receive() external payable {}\r\n\r\n    // once enabled, can never be turned off\r\n    function enableTrading() external onlyOwner {\r\n        tradingActive = true;\r\n        swapEnabled = true;\r\n    }\r\n\r\n    // remove limits after token is stable\r\n    function removeLimits() external onlyOwner returns (bool) {\r\n        limitsInEffect = false;\r\n        return true;\r\n    }\r\n\r\n    // change the minimum amount of tokens to sell from fees\r\n    function updateSwapTokensAtAmount(uint256 newAmount)\r\n        external\r\n        onlyOwner\r\n        returns (bool)\r\n    {\r\n        require(\r\n            newAmount >= (totalSupply() * 1) / 100000,\r\n            \"Swap amount cannot be lower than 0.001% total supply.\"\r\n        );\r\n        require(\r\n            newAmount <= (totalSupply() * 5) / 1000,\r\n            \"Swap amount cannot be higher than 0.5% total supply.\"\r\n        );\r\n        swapTokensAtAmount = newAmount;\r\n        return true;\r\n    }\r\n\r\n    function updateMaxTxnAmount(uint256 newNum) external onlyOwner {\r\n        require(\r\n            newNum >= ((totalSupply() * 1) / 1000) / 1e18,\r\n            \"Cannot set maxTransactionAmount lower than 0.1%\"\r\n        );\r\n        maxTransactionAmount = newNum * (10**18);\r\n    }\r\n\r\n    function updateMaxWalletAmount(uint256 newNum) external onlyOwner {\r\n        require(\r\n            newNum >= ((totalSupply() * 5) / 1000) / 1e18,\r\n            \"Cannot set maxWallet lower than 0.5%\"\r\n        );\r\n        maxWallet = newNum * (10**18);\r\n    }\r\n\r\n    function excludeFromMaxTransaction(address updAds, bool isEx)\r\n        public\r\n        onlyOwner\r\n    {\r\n        _isExcludedMaxTransactionAmount[updAds] = isEx;\r\n    }\r\n\r\n    // only use to disable contract sales if absolutely necessary (emergency use only)\r\n    function updateSwapEnabled(bool enabled) external onlyOwner {\r\n        swapEnabled = enabled;\r\n    }\r\n\r\n    function updateBuyFees(\r\n        uint256 _devFee,\r\n        uint256 _liquidityFee\r\n    ) external onlyOwner {\r\n        buyDevFee = _devFee;\r\n        buyLiquidityFee = _liquidityFee;\r\n        buyTotalFees = buyDevFee + buyLiquidityFee;\r\n        require(buyTotalFees <= 10, \"Must keep fees at 10% or less\");\r\n    }\r\n\r\n    function updateSellFees(\r\n        uint256 _devFee,\r\n        uint256 _liquidityFee\r\n    ) external onlyOwner {\r\n        sellDevFee = _devFee;\r\n        sellLiquidityFee = _liquidityFee;\r\n        sellTotalFees = sellDevFee + sellLiquidityFee;\r\n        require(sellTotalFees <= 10, \"Must keep fees at 10% or less\");\r\n    }\r\n\r\n    function excludeFromFees(address account, bool excluded) public onlyOwner {\r\n        _isExcludedFromFees[account] = excluded;\r\n        emit ExcludeFromFees(account, excluded);\r\n    }\r\n\r\n    function updateDevWallet(address newDevWallet)\r\n        external\r\n        onlyOwner\r\n    {\r\n        emit devWalletUpdated(newDevWallet, devWallet);\r\n        devWallet = newDevWallet;\r\n    }\r\n\r\n\r\n    function isExcludedFromFees(address account) public view returns (bool) {\r\n        return _isExcludedFromFees[account];\r\n    }\r\n\r\n    function _transfer(\r\n        address from,\r\n        address to,\r\n        uint256 amount\r\n    ) internal override {\r\n        require(from != address(0), \"ERC20: transfer from the zero address\");\r\n        require(to != address(0), \"ERC20: transfer to the zero address\");\r\n\r\n        if (amount == 0) {\r\n            super._transfer(from, to, 0);\r\n            return;\r\n        }\r\n\r\n        if (limitsInEffect) {\r\n            if (\r\n                from != owner() &&\r\n                to != owner() &&\r\n                to != address(0) &&\r\n                to != address(0xdead) &&\r\n                !swapping\r\n            ) {\r\n                if (!tradingActive) {\r\n                    require(\r\n                        _isExcludedFromFees[from] || _isExcludedFromFees[to],\r\n                        \"Trading is not active.\"\r\n                    );\r\n                }\r\n\r\n                // at launch if the transfer delay is enabled, ensure the block timestamps for purchasers is set -- during launch.\r\n                //when buy\r\n                if (\r\n                    from == uniswapV2Pair &&\r\n                    !_isExcludedMaxTransactionAmount[to]\r\n                ) {\r\n                    require(\r\n                        amount <= maxTransactionAmount,\r\n                        \"Buy transfer amount exceeds the maxTransactionAmount.\"\r\n                    );\r\n                    require(\r\n                        amount + balanceOf(to) <= maxWallet,\r\n                        \"Max wallet exceeded\"\r\n                    );\r\n                }\r\n                else if (!_isExcludedMaxTransactionAmount[to]) {\r\n                    require(\r\n                        amount + balanceOf(to) <= maxWallet,\r\n                        \"Max wallet exceeded\"\r\n                    );\r\n                }\r\n            }\r\n        }\r\n\r\n        uint256 contractTokenBalance = balanceOf(address(this));\r\n\r\n        bool canSwap = contractTokenBalance >= swapTokensAtAmount;\r\n\r\n        if (\r\n            canSwap &&\r\n            swapEnabled &&\r\n            !swapping &&\r\n            to == uniswapV2Pair &&\r\n            !_isExcludedFromFees[from] &&\r\n            !_isExcludedFromFees[to]\r\n        ) {\r\n            swapping = true;\r\n\r\n            swapBack();\r\n\r\n            swapping = false;\r\n        }\r\n\r\n        bool takeFee = !swapping;\r\n\r\n        // if any account belongs to _isExcludedFromFee account then remove the fee\r\n        if (_isExcludedFromFees[from] || _isExcludedFromFees[to]) {\r\n            takeFee = false;\r\n        }\r\n\r\n        uint256 fees = 0;\r\n        uint256 tokensForLiquidity = 0;\r\n        uint256 tokensForDev = 0;\r\n        // only take fees on buys/sells, do not take on wallet transfers\r\n        if (takeFee) {\r\n            // on sell\r\n            if (to == uniswapV2Pair && sellTotalFees > 0) {\r\n                fees = amount.mul(sellTotalFees).div(100);\r\n                tokensForLiquidity = (fees * sellLiquidityFee) / sellTotalFees;\r\n                tokensForDev = (fees * sellDevFee) / sellTotalFees;\r\n            }\r\n            // on buy\r\n            else if (from == uniswapV2Pair && buyTotalFees > 0) {\r\n                fees = amount.mul(buyTotalFees).div(100);\r\n                tokensForLiquidity = (fees * buyLiquidityFee) / buyTotalFees; \r\n                tokensForDev = (fees * buyDevFee) / buyTotalFees;\r\n            }\r\n\r\n            if (fees> 0) {\r\n                super._transfer(from, address(this), fees);\r\n            }\r\n            if (tokensForLiquidity > 0) {\r\n                super._transfer(address(this), uniswapV2Pair, tokensForLiquidity);\r\n            }\r\n\r\n            amount -= fees;\r\n        }\r\n\r\n        super._transfer(from, to, amount);\r\n    }\r\n\r\n    function swapTokensForUSDC(uint256 tokenAmount) private {\r\n        // generate the uniswap pair path of token -> weth\r\n        address[] memory path = new address[](2);\r\n        path[0] = address(this);\r\n        path[1] = USDC;\r\n\r\n        _approve(address(this), address(uniswapV2Router), tokenAmount);\r\n\r\n        // make the swap\r\n        uniswapV2Router.swapExactTokensForTokensSupportingFeeOnTransferTokens(\r\n            tokenAmount,\r\n            0, // accept any amount of USDC\r\n            path,\r\n            devWallet,\r\n            block.timestamp\r\n        );\r\n    }\r\n\r\n    function swapBack() private {\r\n        uint256 contractBalance = balanceOf(address(this));\r\n        if (contractBalance == 0) {\r\n            return;\r\n        }\r\n\r\n        if (contractBalance > swapTokensAtAmount * 20) {\r\n            contractBalance = swapTokensAtAmount * 20;\r\n        }\r\n\r\n        swapTokensForUSDC(contractBalance);\r\n    }\r\n\r\n}"
    }
  },
  "settings": {
    "optimizer": {
      "enabled": true,
      "runs": 200
    },
    "outputSelection": {
      "*": {
        "*": [
          "evm.bytecode",
          "evm.deployedBytecode",
          "devdoc",
          "userdoc",
          "metadata",
          "abi"
        ]
      }
    }
  }
}