fn main() {
    let stdin = std::io::read_to_string(std::io::stdin()).unwrap();
    let mut stdin = stdin.split_ascii_whitespace();

    let n: String = stdin.next().unwrap().parse().unwrap();

    use std::io::Write;
    let mut out = std::io::BufWriter::new(std::io::stdout().lock());
    out.write_all(output(solve(n)).as_bytes()).unwrap();
}

fn solve(n: String) -> String {
    let mut n = n.into_bytes();
    n.reverse();
    let mut n = n
        .chunks(3)
        .map(|n| n.into_iter().map(|n| *n).collect::<Vec<_>>())
        .collect::<Vec<_>>()
        .join(&b',');
    n.reverse();
    String::from_utf8(n).unwrap()
}

fn output(ans: String) -> String {
    ans + "\n"
}