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())
haha = ["1"]
final = []

for i in range(n-1):
    haha.append("0")
    final.append("9")
final.append("9")
hudai = int("".join(final))
result = "".join(haha)
result = int(result)
bina_karone = 0

for i in range(result, hudai + 1):
    if(i % t == 0):
        bina_karone = i
        break

if bina_karone > 0:
    print(bina_karone)
else:
    print(-1)