CF584A.Olesya and Rodion

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.

奥列西娅喜欢由 $n$ 位数字组成的数，而罗迪翁只喜欢能被 $t$ 整除的数。请找出一个同时满足二者偏好的数。

你的任务是：给定 $n$ 和 $t$，输出一个严格大于零、恰好由 $n$ 位数字组成且能被 $t$ 整除的整数。如果不存在这样的数，则输出 $-1$。

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.

单行输入包含两个数字 $n$ 和 $t$（$1 ≤ n ≤ 100$，$2 ≤ t ≤ 10$）——分别表示数字的长度以及该数字应能被整除的数。

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.

输出一个满足条件的正整数（不能有前导零）——即该问题的答案；如果不存在这样的数，则输出 -1。若存在多个可能的答案，输出其中任意一个即可。