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());c=0;j=0
if n==1 and t==10 :
    print("-1")
elif n==1 and t<10 :
    print(t)
else :
    for i in range(pow(10,n-1)+1,pow(10,n)-1) :
        if i%t==0 :
            j=i
            c=1
            break
    if c==1 :
        print(j)
    else :
        print("-1")