#include <iostream>
#include <string>

using namespace std;

int main() {
    int N;
    cin >> N;
    string S;
    cin >> S;

    int count_CPCTF = 0;

    // "CPCTF"の出現回数を数える
    for (int i = 0; i <= N - 5; i++) {
        if (S.substr(i, 5) == "CPCTF") {
            count_CPCTF++;
            // "CPCTF"を"-"に置換する
            S.replace(i, 5, "-");
        }
    }

    // "CPCTCPC"の出現回数を数える
    for (int i = 0; i <= N - 8; i++) {
        if (S.substr(i, 8) == "CPCTCPC") {
            count_CPCTF++;
        }
    }

    cout << count_CPCTF << endl;

    return 0;
}