fn main() {
    let s = read::<String>();
    let mut st = String::new();
    let s = s.chars()
        .map(|c| if c.is_uppercase() { c.to_lowercase().nth(0) } else { c.to_uppercase().nth(0) })
        .map(|c| c.unwrap())
        .fold((), |_, c| { st.push(c) });
    println!("{}", st);
}

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()
}