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.*;
public class Velas{
	public static void main (String[]args){	
		Scanner sc = new Scanner(System.in);
		double a = sc.nextInt();
		double b = sc.nextInt();
		double s = 0;
		s = s + a;
		while ((a/b) > 0){
			a = a/b;
			s = s + a;
		}
		Double d = new Double(s);
		int i = d.intValue();
		System.out.println(i);
		
	
	}
}