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:
# -*- coding: utf-8 -*-
"""
Created on Fri May 24 18:25:16 2019

@author: SANDEEP GHANTA
"""
n,t=map(int,input().split())
num=int(str(1)+str(0)*(n-1))
final=int(str(9)+str(9)*(n-1))
x=0
while num<=final:
  if num%t==0:
    print(num)
    x=1
    break
  num+=1
if x==0:
   print(-1)