File size: 964 Bytes
ffea3ed
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
There are 3 heroes and 3 villains, so 6 people in total.

Given a positive integer $n$. Find the smallest integer whose decimal representation has length $n$ and consists only of $3$s and $6$s such that it is divisible by both $33$ and $66$. If no such integer exists, print $-1$.

The first line contains a single integer $t$ ($1\le t\le 500$) — the number of test cases.

The only line of each test case contains a single integer $n$ ($1\le n\le 500$) — the length of the decimal representation.

For each test case, output the smallest required integer if such an integer exists and $-1$ otherwise.

For $n=1$, no such integer exists as neither $3$ nor $6$ is divisible by $33$.

For $n=2$, $66$ consists only of $6$s and it is divisible by both $33$ and $66$.

For $n=3$, no such integer exists. Only $363$ is divisible by $33$, but it is not divisible by $66$.

For $n=4$, $3366$ and $6666$ are divisible by both $33$ and $66$, and $3366$ is the smallest.