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())
count=0
if(t>pow(10,n)):
    print(-1)
    count=1
elif(t>pow(10,n-1) and t<pow(10,n)):
    print(t)
    count=1
else:
    for i in range (pow(10,n-1),pow(10,n)):
        if(i%t==0):
            print(i)
            count=1
            break
    if(count==0):
        print(-1)