// Converts all lower case alphabetic characters to upper case 
// characters, and vice versa.  All others are left untouched.
#include <iostream.h>
#include <ctype.h>

void main() {
    char ch;						// Input character
    
    for ( ;; ) {
	cin.get(ch);
      if ( cin.fail() ) break;
	if (isupper(ch)) {
	    cout << (char) tolower(ch);
	} else if (islower(ch)) {
	    cout << (char) toupper(ch);
	} else {
	    cout << ch;
	} // if
    } // for
} // main