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:
import sys
sys.version
n,t= map(int, input().split())
if n>=1 or n<=100 and t>=2 or t<=10:
    maaxi = pow(10,n)
    if(n!=1):
        minn = pow(10, n-1)
    else:
        minn = 1
        if t == 9:
            maaxi = 10
        else:
            maaxi = 9
    if maaxi == 9 and t == 10:
        print("-1")
    else:
        for i in range (minn,maaxi):
            if i % t == 0:
                print(i)
                break