fn main() {
    let mut input = String::new();
    std::io::stdin().read_line(&mut input).unwrap();
    
    unsafe {
        let cc = input.as_bytes_mut();
    
        for i in 0..cc.len() {
            if 65 <= cc[i] && cc[i] <= 90 {
                cc[i] += 32;
            }
            else if 97 <= cc[i] && cc[i] <= 122 {
                cc[i] -= 32;
            }
        }

        let output = String::from_utf8_lossy(cc);

        println!("{}", output);
    }
}