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 PYTHON3):

Solution:
# CF584-D2-A - Olesya and Rodion
# https://codeforces.com/contest/584/problem/A
#
# Author: eloyhz
# Date: Sep/01/2020


if __name__ == '__main__':
    n, t = [int(x) for x in input().split()]
    x = 10 ** (n - 1)
    if n == 1:
        print(-1 if t == 10 else t)
    elif t == 10:
        print(x)
    else:
        print(x * t)