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:
x,t=input("").split(" ")
x=int(x)
t=int(t)
number =1
for i in range(1,x):
	number=number*10
number2=number*10
ans=-1
#print(number)
#print(number2)
while(number<number2):
	if(number%t==0):
		ans=number
		break
	else:
		number=number+1
print(ans)