Codeforce 584A - Olesya and Rodion

Olesya loves numbers consisting of n digits, and Rodion only likes numbers that are divisible by t. Find some number that satisfies both of them.

Your task is: given the n and t print an integer strictly larger than zero consisting of n digits that is divisible by t. If such number doesn't exist, print - 1.

Input

The single line contains two numbers, n and t (1 ≤ n ≤ 100, 2 ≤ t ≤ 10) — the length of the number and the number it should be divisible by.

Output

Print one such positive number without leading zeroes, — the answer to the problem, or  - 1, if such number doesn't exist. If there are multiple possible answers, you are allowed to print any of them.

Examples

input

3 2

output

712

 #include <iostream>
 #include <stdio.h>
 #include <algorithm>
 #include <cstring>
 #include <sstream>
 using namespace std;
 const int maxn = 1e9+;
 #define N 10005
 int main()
 {
         int n,t,i;
         scanf("%d %d", &n, &t);
         if(n==&&t==){
             printf("-1\n");
         }
         else{
             if(t==){
                 t=;
             }
             printf("%d",t);
             for(i=;i<n-; i++)  {
                 printf("");
             }
             printf("\n");
         }
     return ;
 }