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:
t,n=map(int,input().split())
for i in range(1,11):
    result=int('1'*(t-1)+str(i))
    if result%n==0:
        if len(str(result))==t:
           print(result)
           break
        else:
            result=str(result)[1:]
            if int(result)==0:
                print(-1)
                break
            else:
                print(result)
                break