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 JAVA):

Solution:
/*
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 */


/**
 *
 * @author DHARMENDRA TIWARI
 */import java.util.Scanner;
public class RODION {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        Scanner in=new Scanner(System.in);
        int n=in.nextInt(),t=in.nextInt();
        if((""+t).length()>n){
            System.out.println("-1");
        }else{
            String s=""+t;
            for(int i=s.length();i<n;i++){
                s=s+"0";
            }System.out.println(s);
        }
        // TODO code application logic here
    }
    
}