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:
n,t = map(int,input().split())

if(t==2 or t==4 or t ==8):
	print("8"+"0"*(n-1))
elif(t==3 or t==9):
	print("9"+"0"*(n-1))
elif(t==5):
	print("5"+"0"*(n-1))
elif(t==6):
	print("6"+"0"*(n-1))
elif(t==7):
	print("7"+"0"*(n-1))
else:
	if n>1:
		print("10"+"0"*(n-2))
	else:
		print("-1")