using System;

public class Program {
    public static void Main() {
        int x = int.Parse(Console.ReadLine());
        int y = int.Parse(Console.ReadLine());
        double limit = double.Parse(Console.ReadLine());
        int ans;
        if (y < 0) ans = 2;
        else if (x != 0) ans = 1;
        else ans = 0;
        ans += (int)(Math.Ceiling(Math.Abs(x)/limit) + Math.Ceiling(Math.Abs(y)/limit));
        Console.WriteLine(ans);
    }
}