#include <iostream>
#include <string>
#include <cctype>

using namespace std;

string letter_case_switch(const string& str) {
    string result = str;
    if (str.size() == 0)
        return result;  
    result[0] = isupper(result[0]) ? tolower(result[0]) : toupper(result[0]);
    return result;
}

int main() {
        string meow;
        cin >> meow;
        cout << letter_case_switch(meow) << endl;
}
