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:


n, t = map(int, input().split())
data = [9 for i in range(n)]
result = -1

if n == 1 and t <= 9:
    print(t)
    exit()

def get_result():
    global result

    for i in range(n):
        for j in range(8, -1, -1):
            data[-i - 1] = j
            sum_data = int(''.join(map(str, data)))

            if sum_data % t == 0 and sum_data != 0:
                result = ''.join(map(str, data))

                return

get_result()
print(result)