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())
flag=False
for i in range(10**(n-1),(10**n)-1):
      if i%t==0:
            print(i)
            flag =True
            break
if flag ==False and n==1 and t>=10:  
  print(-1)          
elif flag ==False and n!=1:
  print(-1)      
elif n==1 and flag ==False:
  print(t)