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:
a,b=input().split()
a=int(a)
b=int(b)
c=""
for i in range(1,a+1):
	d=i
	if i>9:
		d=i%10
	c=c+str(d)
c=int(c)
while c%b!=0:
	c=c+1;
c=str(c)
if len(c)!=a:
	print(-1)
else:
	print(c)