#include <iostream>
//#include <vector>
//#include <iomanip>

using namespace std;

int main()
{
	string s;
	cin >> s;

	for (int i = 0; i < (int)s.length(); i++)
	{
		if ('A' <= s[i] && s[i] <= 'Z')
			s[i] += -'A' + 'a';
		else if('a' <= s[i] && s[i] <= 'z')
			s[i] += -'a' + 'A';
	}

	cout << s << endl;

	return 0;
}