using System;
using System.Collections.Generic;
using System.Linq;

public class yukicoder
{
    public static void Main()
    {
        double n = double.Parse(Console.ReadLine());
        
        string s = Convert.ToString((int)Math.Pow(2, n) - 1, 2);
        
        int ans = 0;
        
        foreach(char c in s)
        {
            if(char.IsDigit(c))
                ans = ans + int.Parse(c.ToString());
        }
        
        Console.WriteLine(ans);
        
    }
}