using System;

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

            var diff_x = Math.Ceiling((double)Math.Abs(X) / L);
            var diff_y = Math.Ceiling((double)Math.Abs(Y) / L);
            var turn_count = 0;
            turn_count += Y < 0 ? 1 : 0;
            turn_count += X != 0 ? 1 : 0;
            turn_count += X == 0 && Y < 0 ? 1 : 0;

            Console.WriteLine(diff_x + diff_y + turn_count);
        }
    }
}