5 3
 1000 3
 777 17
 4 3
 2 2
 100 4
 10 4
 999 2
 6 4
 1 2
 17 3
 1 4
 26 8
 91 5
 1 3
 1000 2
 20 3
 9 4
 123 5
 1000 1000
 3 2
 3 3
 80 970
 1000 4
 1 1000

7
 1499
 825
 5
 3
 133
 13
 1997
 7
 1
 25
 1
 29
 113
 1
 1999
 29
 11
 153
 1001
 5
 4
 80
 1333
 1

import java.lang.*;
import java.util.Scanner;
import java.util.Arrays;

public class Main {

    public static Scanner in = new Scanner(System.in);

    public static void main(String[] args) {
        int a = in.nextInt();
        int b = in.nextInt();
        int c = 0;
        int r = 0;
        while (a > 0)
        {
            c += a;
            r += a % b;
            if (r == b) {
                r = 1;
                c ++;
            }
            a /= b;
        }

        System.out.println(c);
    }
}
