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())

mini  =  10**(n-1)
maxi  =  (10**n)-1

counter = mini //  t  

while 1:
   if (t*counter <=maxi) and (t*counter>=mini):
       print(t*counter)
       break
   elif t*counter > maxi:
       print(-1)
       break
   counter += 1