using System;

public class Program

{

    public static void Main()

    {

        string whatThePlayerSays = Console.ReadLine();

        int number = int.Parse(whatThePlayerSays);

        Console.WriteLine(number + number);

        /*

        whatThePlayerSays = whatThePlayerSays.ToUpper();

        if(whatThePlayerSays == "GGWP")

        {

            Console.WriteLine("Thanks!");

        }

        else

        {

            Console.WriteLine("I don't understand :(");

            */

        }

    }

}