#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
  #include "settings/debug.cpp"
  #define _GLIBCXX_DEBUG
#else
  #define Debug(...) void(0)
#endif
#define rep(i, n) for (int i = 0; i < (n); ++i)
using ll = long long;
using ull = unsigned long long;

int main() {
  int n;
  string s;
  cin >> n >> s;
  string t = "";
  for (char c : s) {
    t += c;
    if (t.size() >= 7 && t.substr(t.size() - 7) == "CPCTCPC") {
      rep(_, 7) t.pop_back();
      t += "CPCTF";
    }
  }
  int ans = 0;
  rep(i, t.size()) {
    if (t.substr(i, 5) == "CPCTF") ans++;
  }
  cout << ans << endl;
  return 0;
}