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

    x.sort_unstable();
    x.reverse();

    let last = x[x.len() - 1];
    match x.iter().rposition(|&n| n != last) {
        None => println!("-1"),
        Some(0) if last == '0' => println!("-1"),
        Some(i) => {
            let j = x.iter().position(|&n| n == last).unwrap();
            x.swap(i, j);

            let answer: String = x.iter().collect();

            println!("{answer}");
        }
    }
}