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:
def findNumber(n, d): 
    ans = "" 
    if (d != 10) : 
        ans += str(d) 
        for i in range(1,n): 
            ans += '0'
    else : 
        if (n == 1): 
            ans += "-1"
        else : 
            ans += '1'
            for i in range(1,n): 
                ans += '0'
  
    return ans 

l1 = [int(i) for i in input().split(" ")]
print(findNumber(l1[0], l1[1]))