import java.util.Scanner;
public class Main {
	public static void main(String[] args) {
		//System.out.println("パスワード");
		Scanner scanner = new Scanner(System.in);
		String pw = scanner.next();
		scanner.close();
		String[] pw_1 = new String[pw.length()];
		for(int i = 0; i < pw.length(); i++) {
			String c = pw.substring(i,i+1);
			if( c.matches("[A-Z]{1}")) {
				pw_1[i] = c.toLowerCase();
			}else if(c.matches("[a-z]{1}")) {
				pw_1[i] = c.toUpperCase();
			}else {
				//System.out.println("無効な文字列です");
				//System.exit(1);
			}
		}
		for( int i = 0; i < pw.length(); i++) {
			String s = pw_1[i];
			System.out.print(s);
		}
	}
}