import java.util.*;
import java.lang.*;
import java.io.*;

public class Main
{
    public static void main (String[] args) throws java.lang.Exception
    {
        Scanner sc = new Scanner(System.in);
        String n = sc.next();
        int k = sc.nextInt();
        if(n.length()==1){
          System.out.println(n);
        }
        else{
        long a = 0;
          for(int i=0;i<n.length();i++)a+=(n.charAt(i)-'0');
          a*=k;
        System.out.println(super_digit(a));
        }
    }

    public static long super_digit(long a)
    {
        if(a>0 && a<10)
        {
          return a;
        }
        int sum=0;
      while(a>0){
        sum+=a%10;
        a/=10;
      }
        return super_digit( sum);
    }
}