import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int X = sc.nextInt();
		int Y = sc.nextInt();
		int L = sc.nextInt();
		sc.close();
		int xStep = Math.abs(X)/L;
		int yStep = Math.abs(Y)/L;
		if(X%L!=0){
			xStep++;
		}
		if(Y%L!=0){
			yStep++;
		}
		int total = yStep + xStep;
		if(Y<0){
			total += 2;
		}else if(Y>=0&&X==0){

		}else{
			total += 1;
		}
		System.out.println(total);
	}// mainmethod

} // class