#include <bits/stdc++.h>

using namespace std;
using ll = long long;
constexpr int INF = (1u << 31) - 1;

int main() {
  int N;
  string S;
  cin >> N >> S;
  // CPCTとなっている状態
  string n;
  for (int i = 0; i < N; i++) {
    if (i + 3 < N && S[i] == 'C' && S[i + 1] == 'P' && S[i + 2] == 'C' &&
        S[i + 3] == 'T') {
      if (i + 6 < N && S[i + 4] == 'C' && S[i + 5] == 'P' && S[i + 6] == 'C') {
        n += "CPCTF";
        i += 7;
        continue;
      }
    }
    n.push_back(S[i]);
  }
  ll ans{};
  for (int i = 0; i + 4 < N; i++) {
    if (n.substr(i, 5) == "CPCTF") ans++;
    // cout << n.substr(i, 5) << endl;
  }
  cout << ans << endl;
}