Problem Statement

You are given positive integers N and M. Find the maximum positive integer X that satisfies all of the following conditions.

• X is a positive integer less than 10^N, and all digits in the decimal representation of X are the same.
• X is a multiple of M.

If no positive integer X satisfies the conditions, print -1.

Input

The input is given from Standard Input in the following format:
N M

Output

Print the maximum positive integer X that satisfies all of the conditions, or -1 if no such positive integer X exists.

Constraints

• $1\leq N\leq 10^5$
• $1\leq M\leq 10^9$

Sample Input 1

7 12

Sample Output 1

888888

Four positive integers X satisfy the conditions: 444, 888, 444444, 888888. The answer is the maximum of them, which is 888888.

Sample Input 2

9 12

Sample Output 2

888888888

Six positive integers X satisfy the conditions: 444, 888, 444444, 888888, 444444444, 888888888.

Sample Input 3

1 3

Sample Output 3

9

Three positive integers X satisfy the conditions: 3, 6, 9.

Sample Input 4

1000 25

Sample Output 4

-1

No positive integers X satisfy the conditions.

Sample Input 5

30 1

Sample Output 5

999999999999999999999999999999

见题面 Input 部分

见题面 Output 部分