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

int main()
{
    string s;
    cin >> s;
    for (int i = 0; i < s.size(); i++) {
        if (isupper(s.at(i))) {
            s.at(i) = tolower(s.at(i));
        } else if (islower(s.at(i))) {
            s.at(i) = toupper(s.at(i));
        }
    }
    cout << s << endl;
}