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:
line=input().split(" ")
n= int(line[0])
t= int(line[1])
x=0
num=""
if t==2 or t==4 or t==8:
    for i in range(n):
        num+="8"
if t==3 or t==9:
    num+="9"
    for i in range(n-1):
        num+="0"
if t==6:
    num+="6"
    for i in range(n-1):
        num+="0"
if t==5 or t==10:
    num+="5"
    for i in range(n-1):
        num+="0"
if t==7:
    mult7=7
    while len(str(mult7))<n:
        mult7*=7
    num=str(mult7)
if n==1 and t==10:
    x=1
    print(-1)
if x==0:
    print(num)