#include <bits/stdc++.h>
#define REP(i, n) for(int i = 0; i < n; i++)
#define REPR(i, n) for(int i = n; i >= 0; i--)
#define FOR(i, m, n) for(int i = m; i < n; i++)
#define INF 2e9
#define ALL(v) v.begin(), v.end()
using namespace std;
typedef long long ll;
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    string s, ans;
    cin >> s;

    REP(i, s.size())
    {
        if('A' <= s[i] && s[i] <= 'Z') {
            s[i] = s[i] + ('a' - 'A');
        }else
        {
            s[i] = s[i] - ('a' - 'A');
        }
    }
    cout << s << endl;
}