using System;
using System.Linq;

class Program
{
    static void Main(string[] args)
    {
        int ew = int.Parse(Console.ReadLine());

        if (ew < 0)
        {
            ew *= -1;
        }

        int ns = int.Parse(Console.ReadLine());
        int range = int.Parse(Console.ReadLine());
        int count = 0;

        if (ns != 0)
        {
            if (ns < 0)
            {
                count += 2;
            }

            count += ns / range;
            if (ns % range > 0)
            {
                count++;
            }
        }

        if (ew != 0)
        {
            count++;

            count += ew / range;
            if (ew % range > 0)
            {
                count++;
            }
        }

        Console.WriteLine(count);
        Console.ReadLine();
    }
}