using System;
using System.Collections.Generic;
using System.Collections;
using System.Linq;
using System.Text;
using System.Numerics;
using sc = Scanner;

class Program
{
    static void Main(string[] args)
    {
        Solve();
#if DEBUG
        System.Console.WriteLine("続行するには何かキーを押してください．．．");
        System.Console.ReadKey();
#endif

    }

    /// <summary>
    /// ここでとく
    /// </summary>
    static void Solve()
    {
        int n = sc.NextInt();
        if (n==0)
        {
            Console.WriteLine(4);
            return;
        }
        double answer = 3;

        for (int i = 1; i < n; i++)
        {
            answer *= 0.75;

        }
        Console.WriteLine(answer);
        /* 4^(k-1)A_k = 3^k が数学的帰納法によって証明できる(k >= 0)　0でもなぜかいけてる　dpには4^k-1-1A_kが格納できてる
        BigInteger[] dp = new BigInteger[n+10];
        dp[0] = 4;
        dp[1] = 3;
        dp[2] = 9;
        BigInteger s1 = 1;
        BigInteger s2 = 4;
        for (int i = 3; i < n+1; i++)
        {
            dp[i] = 19 * dp[i - 1] - 12*4*dp[i - 2];
            s1 *= 4;
            s2 *= 4;
        }
        BigInteger p = 4;
        for (int i = 2; i < n; i++)
        {
#if DEBUG
            Console.WriteLine();
#endif 
        }
        */
#if DEBUG
        Console.WriteLine("local check"); // Visual Studioのローカル変数チェック用 MainにいくとSolve内のローカル変数消えちゃう
#endif 

    }

    
}

/// <summary>
/// Java風のスキャナー，自作（某最速の人を参考）
/// </summary>
public static class Scanner
{
    public static string NextString()
    {
        string tmp = "";
        while (true)
        {
            string readData = char.ConvertFromUtf32(Console.Read());
            if (readData == " " || readData == "\n")
                break;
            tmp += readData;
        }
        return tmp;
    }

    public static string[] NextStrArray()
    {
        return Console.ReadLine().Split(' ');
    }

    public static long[] NextLongArray()
    {
        string[] s = NextStrArray();
        long[] a = new long[s.Length];
        for (int i = 0; i < a.Length; i++)
        {
            a[i] = long.Parse(s[i]);
        }
        return a;
    }
    public static int[] NextIntArray()
    {

        string[] s = NextStrArray();
        int[] a = new int[s.Length];
        for (int i = 0; i < a.Length; i++)
        {
            a[i] = int.Parse(s[i]);
        }
        return a;
    }
    public static int NextInt()
    {
        string tmp = "";
        while (true)
        {
            string readData = char.ConvertFromUtf32(Console.Read());
            if (readData == " " || readData == "\n")
                break;
        
            tmp += readData;
        }
        return int.Parse(tmp);
    }
    public static double NextDouble()
    {
        string tmp = "";
        while (true)
        {
            string readData = char.ConvertFromUtf32(Console.Read());
            if (readData == " " || readData == "\n")
                break;
            tmp += readData;
        }
        return double.Parse(tmp);
    }
    public static long NextLong()
    {
        string tmp = "";
        while (true)
        {
            string readData = char.ConvertFromUtf32(Console.Read());
            if (readData == " " || readData == "\n")
                break;
            tmp += readData;
        }
        return long.Parse(tmp);
    }
    public static double[] NextDoubleArray()
    {
        string[] s = NextStrArray();
        double[] a = new double[s.Length];
        for (int i = 0; i < a.Length; i++)
        {
            a[i] = double.Parse(s[i]);
        }
        return a;
    }
}