import java.util.Scanner;


public class Main {
	public static void main(String[] a) {
		Scanner s=new Scanner(System.in);
		int X=s.nextInt(),Y=s.nextInt(),L=s.nextInt();
		int H=(int)Math.abs(Math.ceil((float)X/L))+(X==0?0:1),V=(int)Math.abs(Math.ceil((float)Y/L))+(Y<0?1:0);
		System.out.println(H+V);
	}
}