using System;
public class Hello
{
    public static void Main()
    {
        string line = System.Console.ReadLine().Trim();
        int X = int.Parse(line);
        X = Math.Abs(X);
        line = System.Console.ReadLine().Trim();
        int Y = int.Parse(line);
        line = System.Console.ReadLine().Trim();
        int L = int.Parse(line);

        int count = 0;

        if (X == 0 && Y == 0)
        {
            System.Console.WriteLine(0);
            return;
        }
        else if (X == 0)
        {
            if (Y > 0)
            {
                count = (int)(Math.Ceiling((double)Y / (double)L));
                System.Console.WriteLine(count);
                return;
            }
            else
            {
                Y = Math.Abs(Y);
                count = (int)(Math.Ceiling((double)Y / (double)L) + 2);
                System.Console.WriteLine(count);
                return;
            }
        }
        else if (Y == 0)
        {
            count += (int)(Math.Ceiling((double)X / (double)L)) + 1;
            System.Console.WriteLine(count);
            return;
        }
        else if (Y > 0)
        {
            count = (int)(Math.Ceiling((double)Y / (double)L));
            count += (int)(Math.Ceiling((double)X / (double)L)) + 1;
            System.Console.WriteLine(count);
            return;

        }
        else
        {
            Y = Math.Abs(Y);
            count = (int)(Math.Ceiling((double)X / (double)L) + 1);
            count = (int)(Math.Ceiling((double)Y / (double)L) + 1);
            System.Console.WriteLine(count);
            return;
        }
    }
}