// No.163 cAPSlOCK
// https://yukicoder.me/problems/no/163
//
#include <iostream>
#include <sstream>
#include <locale>
using namespace std;

string solve(string &S);


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

    string ans = solve(S);
    cout << ans << endl;
}

string solve(string &S) {
    locale LOC = locale::classic();
    stringstream ss;

    for (char s: S) {
        if (isupper(s))
            ss << tolower(s, LOC);
        else
            ss << toupper(s, LOC);
    }
    return ss.str();
}