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.