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.util.Scanner;

public class A {

    public static void main(String[] args) {

        Scanner s = new Scanner(System.in);

        int a = s.nextInt();
        int b = s.nextInt();

        int h = 0;

        while (a > 1) {
            h += a;
            if (((a / b) + (a % b)) >= b) {
                a /= b;
            } else {
                h += (a % b);
                break;
            }
        }

        System.out.println(h);

    }

}
