use std::io::Read;

fn solve(n: u8) {
    let res: f64 = 1f64 / (n as f64);
    println!("{}", res);
}

fn main() {
    let mut n = String::new();
    std::io::stdin().read_to_string(&mut n).ok();
    let n = n.trim().split('\n').next().unwrap().trim().parse::<u8>().unwrap();
    solve(n);
}