use proconio::input;

fn main() {
	input! {
		k: usize,
	}

    let mut count = 0;

    for i in [2, 3, 5, 7, 11, 13] {
        for j in [4, 6, 8, 9, 10, 12] {
            if i * j == k {
                count += 1;
            }
        }
    }

    println!("{}", count as f64 / 36.0);
}