#include <iostream>
#include <string>

using namespace std;
int main() {
	string S;
	cin >> S;
	for (int i = 0; i < S.length(); i++) {
		if (isupper(S[i]) != 0) S[i] = tolower(S[i]);
		else if (islower(S[i]) != 0) S[i] = toupper(S[i]);
	}
	cout << S << endl;
	return 0;
}