#include <iostream>
#include <string>
using namespace std;
int main() {
  int n; cin >> n;
  string s; cin >> s;
  int count = 0;
  for (int i = 0; i < n - 4; i++) {
    if (s[i] == 'C' && s[i + 1] == 'P' && s[i + 2] == 'C') {
      if (s[i + 3] == 'T' || s[i + 4] == 'F') {
        count++;
      }
    }
  }
  cout << count << endl;
  return 0;
}