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:
from random import randint
import sys
def random_with_N_digits(f):
    range_start = 10**(n-1)
    range_end = (10**n)-1
    x=randint(range_start, range_end)
    return x


n,t=map(int,input().split())
x=random_with_N_digits(n)
if n==1 and t>=10:
    print(-1)
    sys.exit()
    
while x%t !=0:
    x=random_with_N_digits(n)
if x%t==0:
    print(x)