import java.util.*;
import java.util.regex.*;
class A{
	static Scanner s = new Scanner(System.in);
	public static void main(String[] args){
		StringBuilder sb = new StringBuilder(101);
		Matcher m = Pattern.compile("([a-z]+|[A-Z]+)").matcher(s.next());
		while(m.find()){
			String st = m.group();
			if(st.matches("[a-z]+")){
				sb.append(st.toUpperCase());
			}else{
				sb.append(st.toLowerCase());
			}
		}
		System.out.println(sb);
	}
}