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:
#   FILE: olesyaAndRodion.py
#   CodeForces 584A

def main():
    n, t = input().split()
    n, t = int(n), int(t)

    base = (10 ** (n - 1))

    while(base % t != 0):
        base += 1
        strBase = str(base)
        if(len(strBase) > n):
            print(-1)
            return()

    print(base)

    return()

main()