fn main() {
    let mut n = String::new();
    std::io::stdin().read_line(&mut n).ok();
    let n: usize = n.trim().parse().unwrap();

    if n == 0 {
        println!("0");
        return;
    }
    println!("0.{}{}", "142857".repeat(n/6), &"142857"[..(n%6)]);
}