#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define all(x) (x).begin(), (x).end()
using ll = long long;

int main() {
    string s;
    cin >> s;
    for (auto &c : s) {
        if (isupper(c))
            c = tolower(c);
        else if (islower(c))
            c = toupper(c);
    }
    cout << s << endl;
    return 0;
}