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 TV{
public static void main(String[]args){
 Scanner i = new Scanner(System.in);
 int a = i.nextInt();
 int b = i.nextInt();
 int sum =0;
int y = 0;
int h = a;
while(h > 0){
if(h >= b)
sum += h - h % b;

y += h % b;
h = h /b;
if(h ==0 && y > b){
    h =y;
    y =0;
    }
    else if(h ==0 && y < b){
        sum += y;

        }
}



System.out.print(sum);


}
}