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 -*-
# @Date    : 2018-09-28 09:18:53
# @Author  : raj lath (oorja.halt@gmail.com)
# @Link    : link
# @Version : 1.0.0

from sys import stdin

max_val=int(10e12)
min_val=int(-10e12)

def read_int()     : return int(stdin.readline())
def read_ints()    : return [int(x) for x in stdin.readline().split()]
def read_str()     : return input()
def read_strs()    : return [x for x in stdin.readline().split()]


lens, divider = read_strs()
lens = int(lens)
if len(divider) > lens:
    print(-1)
else:
    print(divider + "0" * (lens - len(divider)))