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:
found = False
n, t = input().split(" ")
n = int(n)
t = int(t)

for j in range(10**(n-1), 10**(n) + 1):
    if 10**(n) == t:
        found = True
        print(-1)
        break
    num = j
    if num % t ==0 and not found:
        print(num)
        found = True
        break
if not found:
    print(-1)