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:
from sys import stdin,stdout,maxsize
# mod = int(1e9 + 7);#import re
tup = lambda: map(int, stdin.readline().split())
I = lambda: int(stdin.readline())
lint = lambda: [int(x) for x in stdin.readline().split()]
# S = lambda: stdin.readline().replace('\n', '').strip()
# #def grid(r, c): return [lint() for i in range(r)]
# #def debug(*args, c=6): print('\033[3{}m'.format(c), *args, '\033[0m', file=stderr)
stpr = lambda x  : stdout.write(f'{x}' + '\n')
# star = lambda x : print(' '.join(map(str , x)))
from _collections import defaultdict
n , t = tup()
x = str(t*(n*pow(10,n)))
print(x[:n]) if len(x[:n]) ==n and int(x[:n])%t==0 else print(-1)