use std::io;

fn main() {
    let mut n = String::new();
    io::stdin().read_line(&mut n).ok();
    let n = n.trim().parse::<u64>().unwrap();

    let mut count = 0;
    for p in [2, 3, 5, 7, 11, 13] {
        for c in [4, 6, 8, 9, 10, 12] {
            if p * c == n {
                count += 1;
            }
        }
    }

    println!("{}", f64::from(count) / 36f64);
}