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=list(map(int,input().split()))
x=10**(n[0]-1)
if(n[0]>1):
    t=n[1]
    while True:
        if(x%t!=0):
            x+=1
        elif(x%t==0):
            print(x)
            break
        if(x>10**(n[0])):
            print("-1")
            break
elif(n[0]==1):
    m=1
    t=n[1]
    while True:
        if(m%t!=0):
            m+=1
        if(m%t==0 and m<10):
            print(m)
            break  
        elif(m==10):
            print("-1")
            break