use std::io::*;

fn main() {
    let mut s: String = String::new();
    std::io::stdin().read_to_string(&mut s).ok();
    let mut itr = s.trim().split_whitespace();
    let n: f64 = itr.next().unwrap().parse().unwrap();

    let kousei = 1e6 * n / 1e4;
    let shimin = 1e6 - kousei;
    let p = kousei * 0.99 + shimin * 0.01;
    println!("{:.10}", shimin * 0.01 / p * 100.0)
}