fn run<'a, I: Iterator<Item = &'a str>>(mut scanner: I) {
    macro_rules! scan {
        ([$t:tt; $n:expr]) => ((0..$n).map(|_| scan!($t)).collect::<Vec<_>>());
        (($($t:tt),*)) => (($(scan!($t)),*));
        ([$($t:tt),*]) => ([$(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);)*);
    }
    
    input! {
        s: Bytes,
    }

    let mut p = 0;
    for b in s {
        if b != p {
            print!("{}", b as char);
            p = b;
        }
    }
    println!();
}

fn main() {
    let ref mut buf = Vec::new();
    std::io::Read::read_to_end(&mut std::io::stdin(), buf).ok();
    run(std::str::from_utf8(buf).unwrap().split_whitespace());
}