using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApp1
{
    class Program
    {
        static void Main(string[] args)
        {
            int X = int.Parse(Console.ReadLine());
            int Y = int.Parse(Console.ReadLine());
            int L = int.Parse(Console.ReadLine());
            int ans = 0;

            if (X != 0)
                ans++;
            if (X < 0)
                X = X * -1;
            if (Y < 0)
            {
                Y = Y * -1;
                ans++;
            }
            while (X > 0)
            {
                if(X < L)
                {
                    ans++;
                    break;
                }
                X = X - L;
                ans++;
            }
            while (Y > 0)
            {
                if (Y < L)
                {
                    ans++;
                    break;
                }
                Y = Y - L;
                ans++;
            }
            Console.WriteLine(ans);
        }
    }
}