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;

/**
 * Vasily the Programmer loves romance, so this year he decided to illuminate
 * his room with candles.
 * 
 * Vasily has a candles.When Vasily lights up a new candle, it first burns for
 * an hour and then it goes out. Vasily is smart, so he can make b went out
 * candles into a new candle. As a result, this new candle can be used like any
 * other new candle.
 * 
 * Now Vasily wonders: for how many hours can his candles light up the room if
 * he acts optimally well? Help him find this number.
 * 
 * Input 
 * The single line contains two integers, a and b (1 ≤ a ≤ 1000;
 * 2 ≤ b ≤ 1000).
 * 
 * Output 
 * Print a single integer — the number of hours Vasily can light up the
 * room for.
 * 
 * Sample test(s) 
 * input 
 * 4 2 
 * output 
 * 7 
 * input 
 * 6 3 
 * output 
 * 8 
 * Note 
 * Consider the first sample. 
 * For the first four hours Vasily lights up new candles, then he uses
 * four burned out candles to make two new ones and lights them up. When these
 * candles go out (stop burning), Vasily can make another candle. Overall,
 * Vasily can light up the room for 7 hours.
 * 
 * @Title: A379NewYearCandles.java
 * @author lxh
 * @date Aug 18, 2015 9:23:55 AM
 * 
 */

public class Main {
    public static void main(String[] args) {
        Scanner cin = new Scanner(System.in);
        int a = cin.nextInt();
        int b = cin.nextInt();
        int s = a;
        while (a != 0) {
            s += a / b;
            a /= b;
        }
        System.out.println(s);
    }
}
