import java.util.*;

public class Main {
	static Scanner sc = new Scanner(System.in);
	public static void main(String[] args) {
		int x = Math.abs(sc.nextInt());
		int y = Math.abs(sc.nextInt());
		int leng = sc.nextInt();
		int times = (x+leng-1)/leng + (y+leng-1)/leng;
		if (y < 0) {times += 2;}
		else if (y>0 && x!=0) {times += 1;}
		System.out.println(times);
	}
}