fn main() {
    let mut s = read::<String>().chars().collect::<Vec<_>>();
    s.dedup();
    let s = s.iter().collect::<String>();
    println!("{}", s);
}

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()
}