package yukicoder;

import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Yuki163 {
	
	public static void main(String[] args) {
		
		Scanner scan = new Scanner(System.in);
		String str = scan.next();
		scan.close();
		String[] strarr = str.split("");
		String bigEng = "[A-Z]";
		String smallEng = "[a-z]";
		Pattern p1 = Pattern.compile(bigEng);
		Pattern p2 = Pattern.compile(smallEng);
		
		for (int i = 0; i < strarr.length; i++ ){
			Matcher m = p1.matcher(strarr[i]);
			Matcher m1 = p2.matcher(strarr[i]);

			if(m.find()){
				strarr[i] = strarr[i].toLowerCase();
			}else if(m1.find()){
				strarr[i] = strarr[i].toUpperCase();
			}
		    System.out.print(strarr[i]);
		}
	}
}