import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class RobotOperation{
    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 num_step = 0;
        if(X != 0 && Y >= 0){
            num_step += 1;
        }else if(Y < 0){
            num_step += 2;
        }

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

        if(Y%L == 0){
            num_step += Math.abs(Y)/L;
        }else{
            num_step += Math.abs(Y)/L+1;
        }
        System.out.println(num_step);

    }
}