#include <bits/stdc++.h>
using namespace std;

int main(){
	string str;
	cin >> str;
	for(int i = 0; i < str.size(); i++){
		if(65 <= (int)str[i] || (int)str[i] <= 90) str[i] += 32;
		else if(97 <= (int)str[i] || (int)str[i] <= 122) str[i] -= 32;
	}
	cout << str << endl;
	return 0;
}