import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import java.io.*;
import java.math.*;
import java.text.*;
import java.util.*;

/*
	br = new BufferedReader(new FileReader("input.txt"));
	pw = new PrintWriter(new BufferedWriter(new FileWriter("output.txt")));
	br = new BufferedReader(new InputStreamReader(System.in));
	pw = new PrintWriter(new BufferedWriter(new OutputStreamWriter(System.out)));
 */

public class Main {
	private static BufferedReader br;
	private static StringTokenizer st;
	private static PrintWriter pw;

	public static void main(String[] args) throws IOException	{
		br = new BufferedReader(new InputStreamReader(System.in));
		pw = new PrintWriter(new BufferedWriter(new OutputStreamWriter(System.out)));
		//int qq = 1;
		int qq = Integer.MAX_VALUE;
		//int qq = readInt();
		for(int casenum = 1; casenum <= qq; casenum++)	{
			int a = readInt();
			int b = readInt();
			int r = 0;
			int burn = 0;
			while(a > 0) {
				a--;
				r++;
				if(++burn == b) {
					burn = 0;
					a++;
				}
			}
			pw.println(r);
		}
		pw.close();
	}

	private static void exitImmediately()	{
		pw.close();
		System.exit(0);
	}

	private static long readLong() throws IOException	{
		return Long.parseLong(nextToken());
	}

	private static double readDouble() throws IOException	{
		return Double.parseDouble(nextToken());
	}

	private static int readInt() throws IOException	{
		return Integer.parseInt(nextToken());
	}

	private static String nextToken() throws IOException	{
		while(st == null || !st.hasMoreTokens())	{
			if(!br.ready())	{
				exitImmediately();
			}
			st = new StringTokenizer(br.readLine().trim());
		}
		return st.nextToken();
	}
}
