fn read<T: std::str::FromStr>() -> T {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok();
    s.trim().parse().ok().unwrap()
}

fn main() {
  let input: u64 = read();

  let fizz = input / 3;
  let buzz = input / 5;
  let ans = fizz * 2 + buzz * 2;
  println!("{}", ans)
}