fn run<'a, I, W>(mut scanner: I, mut writer: W)
where
    I: Iterator<Item = &'a str>,
    W: std::io::Write,
{
    macro_rules! scan {
        ([$t:tt; $n:expr]) => ((0..$n).map(|_| scan!($t)).collect::<Vec<_>>());
        (($($t:tt),*)) => (($(scan!($t)),*));
        (Usize1) => (scan!(usize) - 1);
        (Bytes) => (scan!(String).into_bytes());
        ($t:ty) => (scanner.next().unwrap().parse::<$t>().unwrap());
    }
    macro_rules! input {
        ($($($v:ident)* : $t:tt),* $(,)?) => ($(let $($v)* = scan!($t);)*);
    }
    macro_rules! println {
        ($($arg:tt)*) => (writeln!(writer, $($arg)*).ok());
    }
    
    input! {
        n: u64,
    }

    let ans = 5 * n.saturating_sub(3) + n.min(3);
    println!("{}", ans);
}

fn main() {
    let ref mut buf = Vec::new();
    std::io::Read::read_to_end(&mut std::io::stdin(), buf).ok();
    let scanner = unsafe {
        std::str::from_utf8_unchecked(buf).split_ascii_whitespace()
    };

    let stdout = std::io::stdout();
    let writer = std::io::BufWriter::new(stdout.lock());

    run(scanner, writer);
}