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:
def rangeXY(n):
    firstDigit = "1"
    Middles = "0" * (n - 1)

    return int(firstDigit + Middles)


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

    divisible: bool = False

    TheNumber = rangeXY(n)

    while len(str(TheNumber)) == n:
        if(not TheNumber % t):
            divisible = True
            break
        TheNumber += 1

    if(not divisible):
        print(-1)
    else:
        print(TheNumber)


main()