#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define endl "\n"

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

    for (int i = 0; i < s.size(); ++i) {
        if (s[i] >= 'A' && s[i] <= 'Z') {
            s[i] += 32;
        } else if (s[i] >= 'a' && s[i] <= 'z') {
            s[i] -= 32;
        }
    }

    cout << s << endl;
    return 0;
}