1

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

/**
 * Created by zxc on 05.10.2014.
 */
public class G {
    long n;
    long k;
    long P=0;
    void f(long n){
        if (n>k)
        {
            long p=1;
            int x=0;
            while(Math.pow(k, x+1)<n)
            {
                x++;
                if (x%2==1)
                    p=p*k;
            }
            P=P+(long)(n/Math.pow(k,x))*p;
            f((long)(n-((int)(n/Math.pow(k,x))*Math.pow(k,x))));
        }
        else
            P+=n;
    }
    void solve() throws IOException {
        n=nextLong();
        k=nextLong();
        if (k%2==0)
            f(n+1);
        else
            f(n);
        out.println(P);
    }





    void run() throws IOException {
        reader = new BufferedReader(new InputStreamReader(System.in));
        out = new PrintWriter(new OutputStreamWriter(System.out));
        // reader = new BufferedReader(new FileReader("file.in"));
        // out = new PrintWriter(new FileWriter("file.out"));
        tokenizer = null;
        solve();
        reader.close();
        out.flush();
    }

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

    BufferedReader reader;
    StringTokenizer tokenizer;
    PrintWriter out;

    int nextInt() throws IOException {
        return Integer.parseInt(nextToken());
    }

    long nextLong() throws IOException {
        return Long.parseLong(nextToken());
    }

    double nextDouble() throws IOException {
        return Double.parseDouble(nextToken());
    }

    String nextToken() throws IOException {
        while (tokenizer == null || !tokenizer.hasMoreTokens()) {
            tokenizer = new StringTokenizer(reader.readLine());
        }
        return tokenizer.nextToken();
    }
}