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=map(int,input().split())
A=[0]*n
if n==1:
    if t<10:
        print(t)
    else:
        print('-1')
else:
    for i in range(0,10):
        A[n-1]=i
        A[0]=1
        B=[str(i) for i in A]
        b=int(''.join(B))
        if b%t==0:
            print(b)
            break
        else:
            pass