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:
def main():
 b , a = input().split(" ")
 a = int(a)
 b = int(b)
 if(b==1 and a==10):
     print(-1)
 elif(a<10):
     c = 10**(b-1)
     a = a * c
     print(a)
 else:
     c = 10**(b-2)
     a = a * c
     print(a)
if __name__ == "__main__":main()