comefrom: <awangdev>509. Fibonacci Number_1.java
code: public int fibonacci(int n) {
          if (n <= 1) {
              return 0;
          }
          int first = 0;
          int second = 1;
          for (int i = 2; i < n; i++) {
              int temp = second;
              second = first + second;
              first = temp;
          }
          return second;
      }
masked: public int sample_funcname ( int var_0 ) {
    if ( var_0 <= 1 ) {
      return 0 ;
    }
    int var_1 = 0 ;
    int var_2 = 1 ;
    for ( int var_3 = 2 ;
    var_3 < var_0 ;
    var_3 ++ ) {
      int var_4 = var_2 ;
      var_2 = var_1 + var_2 ;
      var_1 = var_4 ;
    }
    return var_2 ;
  }
  