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

int main()
{
    cin.tie(0)->sync_with_stdio(0);

    string S;
    cin >> S;

    for (char c : S) {
        char ans;
        if (isupper(c)) {
            ans = tolower(c);
        } else {
            ans = toupper(c);
        }
        cout << ans;
    }
    cout << endl;
}