fn main() {
    let mut n = String::new();
    std::io::stdin().read_line(&mut n).ok();
    let n: usize = n.trim().parse().unwrap();
    
    let mut dp = vec![vec![0.; 1<<6]; n+1];
    dp[0][0] = 1.;
    for i in 0..n {
        for j in 0..1<<6 {
            if dp[i][j] == 0. { continue; }
            let val = dp[i][j] / 6.;
            for k in 0..6 {
                let nj = (1 << k) | j;
                dp[i+1][nj] += val;
            }
        }
    }
    println!("{}", dp[n][(1<<6)-1]);
}