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:
min_n=5040
x,y=map(int,input().split())
if x>=4:
    print('5040'+"0"*(x-4))
else:
    status=False
    start=int('1'+'0'*(x-1))
    for i in range(start,int('1'+'0'*x)):
        if i%y==0:
            print(i)
            status=True
            break
    if status==False:
        print(-1)