#include <bits/stdc++.h>   using namespace std;   int main() {     int n, cou = 0;     cin >> n;     string s;     cin >> s;     int res = n + 1;     for (int i = 0; i < n; i++) {       if (s[i] ==  H ) cou++;     }     for (int i = 0; i < n; i++) {       int cnt = 0;       for (int j = 0; j < cou; j++) {         if (s[(i + j) % n] ==  T ) cnt++;       }       res = min(res, cnt);     }     cout << res << endl;   }   