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:
import random
a=input()
i=0
m=""
s=""
while a[i]!=" ":
	m=m+a[i]
	i=i+1
n=int(m)
i=i+1
while i<=(len(a)-1):
	s=s+a[i]
	i=i+1
t=int(s)
if n==1 and t==10:
	print("-1")
else:
	while True:
		x=random.randrange(pow(10,n-1),pow(10,n))
		if x%t==0:
			print(x)
			break