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] = [int(x) for x in input().split()]
start = 10^(n-1)
# factorize t
factorList = []
i = 2
num = t
while num != 1:
    if num % i == 0:
        factorList.append(i)
        while num % i == 0:
            num /= i
    i += 1
a = 1
for factor in factorList:
    a *= factor
while len(str(a)) < n:
    a *= factorList[0]
if len(str(a)) == n:
    while len(str(a)) == n and a % t != 0:
        a *= factorList[0]
    print(a)
else:
    print(-1)