fn read() -> i32 {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).unwrap();
    s.trim().parse().unwrap()
}

fn main() {
    let n = read();
    let m = 100000;
    let mut ans = 0f64;
    let mut sum = 0f64;
    for b in 2..m {
        sum += 1f64 / (b - 1) as f64;
        ans -= sum * (1f64 / b as f64).powi(n + 1);
    }
    let mut sum = 0f64;
    for a in 1..m {
        sum += 1f64 / a as f64;
        ans += sum * (1f64 / a as f64).powi(n + 1);
    }
    println!("{:.7}", ans);
}