// use std::ops::{Index, IndexMut};
// use std::cmp::{Ordering, min, max};
// use std::collections::{BinaryHeap, BTreeMap};
// use std::collections::btree_map::Entry::{Occupied, Vacant};
// use std::clone::Clone;

fn getline() -> String{
    let mut res = String::new();
    std::io::stdin().read_line(&mut res).ok();
    res
}

macro_rules! split {
    ($x: expr) => {
        ($x).trim().split(' ').collect()
    }
}

macro_rules! parse {
    ($x: expr) => {
        ($x).parse().unwrap()
    }
}

macro_rules! readl {
    ($t: ty) => {
        {
            let s = getline();
            let iv: Vec<_> = split!(s);
            let mut iter = iv.into_iter();
            iter.next().unwrap().parse::<$t>().unwrap()
        }
    };
    ($( $t: ty),+ ) => {
        {
            let s = getline();
            let iv: Vec<_> = split!(s);
            let mut iter = iv.into_iter();
            ($(iter.next().unwrap().parse::<$t>().unwrap(),)*) 
        }
    };
}

macro_rules! rvec {
    ($x: expr) => {
        ($x).into_iter().map(|x| parse!(x)).collect()
    }
}

macro_rules! readlvec {
    ($t: ty) => {
        {
            let s = getline();
            let iv: Vec<_> = split!(s);
            iv.into_iter().map(|x| x.parse().unwrap()).collect::<Vec<$t>>()
        }
    }
}

macro_rules! debug {
    ($x: expr) => {
        println!("{}: {}", stringify!($x), $x)
    }
}

fn printvec<T>(v: &Vec<T>) where T: std::fmt::Display {
    for (i,e) in v.into_iter().enumerate() {
        if i != 0 {
            print!(" ");
        }
        print!("{}", e);
    }
    println!("");
}

fn main() {
    let n = readl!(usize);
    let mut dp = vec![vec![0_f64; 7]; n+1];
    dp[0][0] = 1.0;
    for i in 0..n {
        for j in 0..6 {
           dp[i+1][j+1] += dp[i][j]*(6.0-j as f64)/6.0;
           dp[i+1][j] += dp[i][j]*(j as f64)/6.0;
        }
        dp[i+1][6] += dp[i][6];
    }
    println!("{}", dp[n][6]);
}