fn main() {
    let stdin = std::io::read_to_string(std::io::stdin().lock()).unwrap();
    let mut stdin = stdin.split_ascii_whitespace();

    let n: usize = stdin.next().unwrap().parse().unwrap();

    use std::io::Write;
    std::io::stdout()
        .lock()
        .write_all(output(solve(n)).as_bytes())
        .unwrap();
}

fn solve(n: usize) -> f64 {
    let mut dp = [[0.0; 1 << 6]; 2];
    dp[0][0] = 1.0;
    (0..n).for_each(|i| {
        dp[(i & 1) ^ 1].fill(0.0);
        (0..(1 << 6))
            .for_each(|j| (0..6).for_each(|k| dp[(i & 1) ^ 1][j | (1 << k)] += dp[i & 1][j] / 6.0))
    });
    dp[n & 1][(1 << 6) - 1]
}

fn output(ans: f64) -> String {
    ans.to_string() + "\n"
}