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=list(map(int, input().split()))
smallest_number=10**(n[0]-1)
if n[0]==1:
    if n[1]<10:
        print(n[1])
    else:
        print("-1")
else:
    for i in range(smallest_number):
        if smallest_number%n[1]==0:
            print(smallest_number)
            break
        smallest_number+=1