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 step=sc.nextInt();
        
        int count=0;
        int abs_x=Math.abs(x);
        int abs_y=Math.abs(y);
        
        if(y>0){
            while(y>step){
                y-=step;
                count++;
            }
            count++;
            if(x!=0){
                count++;
                while(abs_x>step){
                    abs_x-=step;
                    count++;
                }
                count++;
            }else{
                ;
            }
        }else if(y==0){
            if(x!=0){
                count++;
                while(abs_x>step){
                    abs_x-=step;
                    count++;
                }
                count++;
            }else{
                ;
            }
        }else{
            if(x!=0){
                count++;
                while(abs_x>step){
                    abs_x-=step;
                    count++;
                }
                count++;
            }else{
                count++;
            }
            count++;
            while(abs_y>step){
                abs_y-=step;
                count++;
            }
            count++;
        }
        System.out.println(count);
        
    }
}