#![allow(unused_imports)]
use {std::cmp::*, std::collections::*, std::io::Write, std::ops::*};

#[allow(unused_macros)]
macro_rules !dbg {($($e :expr ) ,*) =>{#[cfg (debug_assertions ) ] $({let (e ,mut err ) =(stringify !($e ) ,std ::io ::stderr () ) ;writeln !(err ,"{} = {:?}" ,e ,$e ) .unwrap () } ) *} ;}
#[rustfmt::skip] pub fn readln() -> String { let mut line = String::new(); ::std::io::stdin() .read_line(&mut line) .unwrap_or_else(|e| panic!("{}", e)); line }
#[allow(unused_macros)]
macro_rules !read {($($t :tt ) ,*;$n :expr ) =>{{let stdin =::std ::io ::stdin () ;let ret =::std ::io ::BufRead ::lines (stdin .lock () ) .take ($n ) .map (|line |{let line =line .unwrap () ;let mut it =line .split_whitespace () ;_read !(it ;$($t ) ,*) } ) .collect ::<Vec <_ >>() ;ret } } ;($($t :tt ) ,*) =>{{let line =readln () ;let mut it =line .split_whitespace () ;_read !(it ;$($t ) ,*) } } ;}
#[allow(unused_macros)]
macro_rules !_read {($it :ident ;[char ] ) =>{_read !($it ;String ) .chars () .collect ::<Vec <_ >>() } ;($it :ident ;[u8 ] ) =>{Vec ::from (_read !($it ;String ) .into_bytes () ) } ;($it :ident ;usize1 ) =>{$it .next () .unwrap_or_else (||panic !("input mismatch" ) ) .parse ::<usize >() .unwrap_or_else (|e |panic !("{}" ,e ) ) -1 } ;($it :ident ;[usize1 ] ) =>{$it .map (|s |s .parse ::<usize >() .unwrap_or_else (|e |panic !("{}" ,e ) ) -1 ) .collect ::<Vec <_ >>() } ;($it :ident ;[$t :ty ] ) =>{$it .map (|s |s .parse ::<$t >() .unwrap_or_else (|e |panic !("{}" ,e ) ) ) .collect ::<Vec <_ >>() } ;($it :ident ;$t :ty ) =>{$it .next () .unwrap_or_else (||panic !("input mismatch" ) ) .parse ::<$t >() .unwrap_or_else (|e |panic !("{}" ,e ) ) } ;($it :ident ;$($t :tt ) ,+) =>{($(_read !($it ;$t ) ) ,*) } ;}

fn pow(a: f64, n: usize) -> f64 {
    match n {
        0 => 1.0,
        _ => {
            let mut x = pow(a, n >> 1);
            x *= x;
            if n & 1 == 1 {
                x *= a;
            }
            x
        }
    }
}

fn main() {
    let n = read!(usize);
    let mut ans = 0.0;
    let y = 1.0;
    for i in 1.. {
        let x = 1.0 / pow(i as f64, n);
        if x < 1e-10 && x / y < 1e-1 {
            break;
        }
        ans += x;
    }
    println!("{0:.8}", ans);
}