package yukicoder.No48;

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int X = Integer.parseInt(sc.next());
        int Y = Integer.parseInt(sc.next());
        int L = Integer.parseInt(sc.next());

        int sum = 0;

        if (Y > 0) {
            sum += (Y / L);
            if (Y % L != 0) sum++;
        } else {
            sum += 2;
            Y = -Y;
            sum += (Y / L);
            if (Y % L != 0) sum++;
        }

        if (X != 0) {
            sum++;

            X = Math.abs(X);
            sum += (X / L);
            if (X % L != 0) sum++;
        }

        System.out.println(sum);
    }
}