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 $-1$ .

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.

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.