using System;
using System.Linq;
class P
{
    static void Main(string[] _)
    {
        int x = int.Parse(Console.ReadLine());
        int y = int.Parse(Console.ReadLine());
        int l = int.Parse(Console.ReadLine());
        int m = Math.Abs(x) + Math.Abs(y);
        int n = 0;
        if (x == 0 && y == 0)
        {
            n = 0;
        }
        else if (x == 0 || y == 0)
        {
            n = (int)Math.Ceiling(m / (double)l);
        }
        else
        {
            n = 1 + (int)Math.Ceiling(m / (double)l);
        }
        Console.WriteLine(n);
    }
}