Problem: 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

Solution (in CPP):

Solution:
#include <bits/stdc++.h>
using namespace std;
int main() {
  int nilai = 1, i;
  int n, j;
  cin >> n >> j;
  if (n <= 6) {
    for (i = 0; i < n; i++) {
      nilai = nilai * 10;
    }
    nilai = nilai / 10;
    if (j != 10) {
      nilai = nilai * j;
    }
    if (nilai % j == 0)
      cout << nilai;
    else
      cout << -1;
  } else {
    cout << 362880;
    for (i = 1; i <= n - 6; i++) {
      cout << 0;
    }
  }
  return 0;
}