/*
출처:프로그래머스,
https://school.programmers.co.kr/learn/courses/30/lessons/181949
*/

import java.util.Scanner;

public class Solution {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String a = sc.next();
        String[] b= a.split("");
        String c = "";
        for(String alpha: b){
            if(alpha.equals(alpha.toUpperCase()) ) {
                c+=alpha.toLowerCase();
                
            }
            else {
                c+=alpha.toUpperCase();
            }
            
            }
        System.out.print(c);
    }
}