use std::io::{self, BufReader, BufWriter, Read, Write};

fn main() {
    let stdin = io::stdin();
    let stdin = BufReader::new(stdin.lock());
    let stdout = io::stdout();
    let mut stdout = BufWriter::new(stdout.lock());

    let result: Vec<u8> = stdin
        .bytes()
        .filter_map(|b| b.ok())
        .skip_while(|b| b.is_ascii_whitespace())
        .take_while(|b| !b.is_ascii_whitespace())
        .map(|b| {
            if b.is_ascii_lowercase() {
                b.to_ascii_uppercase()
            } else {
                b.to_ascii_lowercase()
            }
        })
        .collect();

    stdout.write(&result).unwrap();
}