using System;

namespace yukicoder
{
    class Program
    {
        static void Main(string[] args)
        {
            double x = int.Parse(Console.ReadLine());
            double y = int.Parse(Console.ReadLine());
            double l = int.Parse(Console.ReadLine());
            double count = 0;
            double ans =0;
            
            if (y ==0)
            {
                if (x != 0)
                {
                    count = 1;
                }
                    
            }else if (x == 0)
            {
                if (y < 0)
                {
                    count = 2;
                }
            }
            else
            {
                if (y > 0)
                {
                    count = 1;
                }
                else
                {
                    count = 2;
                }
            }

            if (x < 0)
            {
                x *= -1;
            }
            if (y < 0)
            {
                y *= -1;
            }
            ans +=Math.Ceiling (x / l);
            ans += Math.Ceiling(y / l);

            ans += count;
            Console.WriteLine(ans);
            
        }

    }
}