using System;

public class Hello
{
    static void Main()
    {
        var n = int.Parse(Console.ReadLine().Trim());
        getAns(n);
    }
    static void getAns(int n)
    {
        var dp = new double[n + 1, 10];
        dp[0, 0] = 1;
        for (int i = 0; i < n; i++)
        {
            for (int j = 0; j <= 6; j++)
            {
                dp[i + 1, j + 1] += dp[i, j] * (6 - j) / 6d;
                dp[i + 1, j] += dp[i, j] * j / 6d;
            }
        }
        Console.WriteLine(dp[n, 6]);
    }
}