fn main() {
    let mut n = String::new();
    std::io::stdin().read_line(&mut n).ok();
    let n = n.trim().chars().collect::<Vec<_>>();

    let mut result = vec![];
    for i in 0..n.len() {
        if i > 0 && i % 3 == 0 {
            result.push(',');
        }
        result.push(n[n.len()-1-i]);
    }
    result.reverse();
    println!("{}", result.iter().map(|c| c.to_string()).collect::<Vec<_>>().join(""));
}