import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int X = sc.nextInt();
        int Y = sc.nextInt();
        int L = sc.nextInt();
        int turn=0;
        int gox=0;
        int goy=0;

        if(X%L==0){
                gox=Math.abs(X/L);
        }else{
                gox=Math.abs(X/L)+1;
        }
        if(Y%L==0){
                goy=Math.abs(Y/L);
        }else{
                goy=Math.abs(Y/L)+1;
        }

        if(Y>=0){
            if(X==0){
                turn=0;
            }else{
                turn=1;
            }
        }else{
            turn=2;
        }

        int r = gox+goy+turn;
        System.out.println( r );
    }
}