#include <iostream>
using namespace std;
int main()
{
	char a;
	cin >> a;
	if(a >= 65 && a <= 90)
	{
		cout << (char)(a+=32);
	}
	else if(a >= 97 && a <= 122)
	{
		cout << (char)(a-32);
	}
	else
	{
		cout << a;
	}
	return 0;
}