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.io .*; 
import java.util.*; 

public class Summ { 
	private void solve() { 
		int a = nextInt();
		int b = nextInt();
		int h = 0;
		while(true) {
		    h += a;
		    a /= b;
		    if(a == 0) break;
		}
		out.println(h);
	}

	public static void main(String[] args) { 
			new Summ().run(); 
	} 

BufferedReader br; 
StringTokenizer st; 
PrintWriter out; 

private void run() { 
try { 
br = new BufferedReader(new InputStreamReader(System.in )); 
out = new PrintWriter(System.out); 
//br = new BufferedReader(new FileReader("birthday.in ")); 
//out = new PrintWriter(new FileWriter("birthday.out")); 
solve(); 
br.close(); 
out.close(); 
} catch (IOException e) { 
e.printStackTrace(); 
} 
} 

private int nextInt() { 
return Integer.parseInt(next()); 
} 

    private String next() { 
        while (st == null || !st.hasMoreTokens()) { 
            try { 
                st = new StringTokenizer(br.readLine()); 
            } catch (IOException e) { 
                e.printStackTrace(); 
                return "END_OF_FILE"; 
            } 
        } 
        return st.nextToken();
    } 
} 
