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:
import random 
def static_size(n):
    start_range=10**(n-1)
    end_range=(10**n)-1
    return random.randint(start_range,end_range)
n,t=input().split()
a,b=int(n),int(t)
k=static_size(a)
count=0
v=(((10**a)-1)-(10**(a-1)))
while(count<=v+13):
    if(k%b==0):
        print(k)
        exit(0)
    else:
        # print(k)
        k=static_size(a)
    count+=1 
print(-1)