using System;

public class Program

{

    public static void Main()

    {

        //Alejandro Campos

        int a = 0, f = 3, num;

        Console.WriteLine("Take a look to the following series.");

        for(int i = 1; i <= 5; i++)

        {

            a = a + f;

            Console.WriteLine(a);

            f = 2*f;

        }

        Console.WriteLine("What position of the series do you want to know?");

        num = int.Parse(Console.ReadLine());

        a = 0;

        f = 3;

        for(int i = 1; i <= num; i++)

        {

            a = a + f;

            f = 2*f;

        }

        Console.WriteLine( a + " is the number on the series that corresponds to the position you asked.");

    }

}