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:
nx , tx = input().split()
n = int(nx)
t = int(tx)
num = 10**(n-1)
while num <= 10**(n-1)+int('8'+(n-1)*'8'):
	if num%t == 0:
		print(num)
		ans = '1'
		break
	else:
		num += 1
		ans = '0'


if ans == '0':
	print('-1')