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:
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#    ┃┈┈┈┣▅╋▅┫┃
#    ┃┈┃┈╰━╰━━━━━━╮
#    ╰┳╯┈┈┈┈┈┈┈┈┈◢▉◣
#     ┃┈┈┈┈┈┈┈┈┈┈▉▉▉
#     ┃┈┈┈┈┈┈┈┈┈┈◥▉◤
#     ┃┈┈┈┈╭━┳━━━━╯
#     ┣━━━━━━┫﻿
n,t = input().split()
n,t = int(n),int(t)
ls=list()
ls.append(t)
if n == 1 and t > 9:
	print(-1)
else:
	while len(ls) < n:
		ls+='0'
#		print(ls)
#		print(len(ls))
	if t >= 10:
		del(ls[-1])
#		print ("lol") 
	for i in ls:
		print(i,end='')
print()