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

 #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 ;

 }

巴特西

Codeforce 584A - Olesya and Rodion

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