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:
#!/usr/bin/python3

def solve(n, t):
	x0 = 1;
	for i in range(1, n):
		x0 *= 10;
	
	
	for x in range(x0, 10 * x0):
		if (x % t == 0):
			return x
	return -1

nums = list(map(int, input().split()))
print(solve(nums[0], nums[1]))