using System;

public class Program

{

    public static int f(int n) {

        if (n <= 1) {

            return n;

        }

        else {

            return 2 * f(n - 1) + 1;

        }

    }

    public static void Main()

    {

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

        Console.WriteLine("f({0})={1}", n, f(n));

    }

    /* f(1) = 1

    f(2) = 2 * f(1) + 1 = 3

    f(3) = 2 * f(2) + 1 = 7

    f(4) = 2 * f(3) + 1 = 15

    f(5) = 2 * f(4) + 1 = 31

    f(6) = 2 * f(5) + 1 = 63

    f(7) = f(f(3)) = 2 * f(6) + 1 = 127

    */

}