import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner koko = new Scanner(System.in);
        int x = koko.nextInt();
        int y = koko.nextInt();
        int l = koko.nextInt();
        int dx = Math.abs(x);
        int dy = Math.abs(y);
        int mx = dx%l;
        int my = dy%l;
        int nx, ny;
        if(mx!=0){
            nx = 1+((dx-mx)/l);
        }else{
            nx =dx/l;
        }
        if(my!=0){
            ny = 1+((dy-my)/l);
        }else{
            ny =dy/l;
        }
        if(x==0&&y==0){
            System.out.println(0);
        }else if(x==0&&y>0){
            System.out.println(ny);
        }else if(x!=0&&y==0){
            System.out.println(nx+1);
        }else if(x!=0&&y>0){
            System.out.println(nx+ny+1);
        }else{
            System.out.println(nx+ny+2);
        }
        }
    }