use std::io::{self, Read};

#[derive(Debug)]
struct Input {
    s: String,
}

fn next_token(cin_lock: &mut io::StdinLock) -> String {
    cin_lock
        .by_ref()
        .bytes()
        .map(|c| c.unwrap() as char)
        .skip_while(|c| c.is_whitespace())
        .take_while(|c| !c.is_whitespace())
        .collect::<String>()
}

fn read_input(cin_lock: &mut io::StdinLock) -> Input {
    Input {
        s: next_token(cin_lock),
    }
}

fn solve(input: &Input, _cin_lock: &mut io::StdinLock) {
    fn invert(c: char) -> char {
        if c.is_ascii_uppercase() {
            c.to_ascii_lowercase()
        } else {
            c.to_ascii_uppercase()
        }
    }

    let r = input.s.chars().map(invert).collect::<String>();
    println!("{}", r);
}

fn main() {
    let cin = io::stdin();
    let mut cin_lock = cin.lock();

    let input = read_input(&mut cin_lock);
    solve(&input, &mut cin_lock);
}