#include <iostream>
using namespace std;

int main() {
	string s;cin>>s;
	for(int i=0;i<s.size();i++)
	{
		if(s[i]>='A'&&s[i]<='Z')s[i]+='a'-'A';
		else s[i]-='a'-'A';
	}
	cout<<s<<endl;
	return 0;
}