using System;
using System.Globalization;

class Program
{
    public static void Main(string[] args)
    {
        int x = int.Parse(Console.ReadLine());
        int y = int.Parse(Console.ReadLine());
        int k = int.Parse(Console.ReadLine());

        int count = 0;

        if (x != 0)
        {
            count++;
        }
        if (y < 0)
        {
            count = Math.Max(2, count+1);
        }
        if (x != 0)
        {
            count += Math.Abs(x)/k;
            if (Math.Abs(x)%k != 0)
            {
                count++;
            }
        }
        if (y != 0)
        {
            count += Math.Abs(y) / k;
            if (Math.Abs(y) % k != 0)
            {
                count++;
            }
        }
        Console.WriteLine(count.ToString(CultureInfo.InvariantCulture));
    }
}