#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;


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


long long sum_initial( string number ){
    long long sum = 0;
    
    for( int i = 0; i < number.size(); i++ ) {
        sum += number[i] - '0';
    }
    
    return sum;
}


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */ 
    string  n;
    int k;
    cin >> n >> k;
    long long repeated = sum_initial(n) * k;
    
    long long result = super_digit(repeated);
    
    cout << result << "\n";
    
    
    
    
    return 0;
}

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

public class Solution {

    public static void main(String[] args) {
        Solution s = new Solution();
        Scanner sc = new Scanner(System.in);
        
        String str_n = sc.next();
        int k = sc.nextInt();
        
        int pSum = Integer.parseInt(s.supdig(str_n));
        pSum *= k;
                        
        String sup = Integer.toString(s.supdig(pSum));
        
        System.out.println(sup);
    }
    
    String supdig(String n) {
        if(n.length() == 1) return n;
        else {
            int np = 0;
            
            for(int i = 0; i < n.length(); i++) {
                np += Character.getNumericValue( n.charAt(i) );    
            }
            
            return supdig(Integer.toString(np));
        }       
    }
    
    int supdig(int n) {
        if(n / 10 == 0) return n;
        else {
            int r = 0;
            
            while(n > 0) {
                r += n % 10;
                n /= 10;
            }
            
            return supdig(r);
        }
    }
}
 

def sup_digits(x,k):
    a = digsum(x)
    return sup_digit(str(int(a)*k))

def sup_digit(x):
    if len(x) <= 1:
        return x
    else:
        return sup_digit( digsum(x) )

def digsum(x):
    return str(sum((int(i) for i in list(x))))


n, k = input().split()
print( sup_digits(n, int(k)))

const N = require('bignumber.js');

let $ = '';

const r = n => n < 10 ? n : f(new N(n).toFixed());

const f = (n, k = 1) => {
  let i = 0;

  for (const c of n) i += +c;

  return r(i * k);
};

process.stdin.on('data', d => $ += d).on('end', () => {
  const [ n, k ] = $.trim().split(/\s+/);
  const ans = f(new N(n).toFixed(), +k);

  console.log(ans);
});

#include <stdio.h>
#include <string.h>
#include <math.h>
#include <stdlib.h>

int main() {
    long long sd=0,h;
    int k;
    int c;
    do{
        c=getchar();
        if(c != ' ')
            sd += c -'0'; 
    }while(c != ' ');
    scanf("%d",&k);
    sd *= k;
    
    while(sd > 10){
        h=0;
        while(sd > 0){
            h+= sd %10;
            sd = sd /10;
        }
        sd =h;
    }
    printf("%lld\n",sd);
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */    
    return 0;
}