7.2.4

import java.util.Scanner;
public class Main {


    static char Change(char c)
    {
        if (c>='a' && c<='z') return (char)(c-'a'+'A');
        else if (c>='A' && c<='Z') return (char)(c-'A'+'a');
        return c;
    }

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String a=in.nextLine();
        char b=a.charAt(0);
        System.out.println(Change(b));
    }
}