using System;
using System.Linq;

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

            int count = X != 0 ? (Math.Abs(X) - 1) / L + 2 : 0;
            count += Y != 0 ? (Math.Abs(Y) - 1) / L + 1 : 0;

            if (Y < 0)
            {
                count++;
                if(X == 0)
                {
                    count++;
                }
            }
            Console.WriteLine(count);
        }
    }
}