#include <iostream>
using namespace std;
int main(void) {
	string s;
	cin >> s;
	for (int i = 0; i < s.size(); ++i) {
		if (65 <= s[i] && s[i] <= 90)
			s[i] += 32;
		else if (97 <= s[i] && s[i] <= 122)
			s[i] -= 32;
	}
	cout << s << endl;
	return 0;
}