#include <iostream>
#include <string>

using namespace std;

int main() {
    int N;
    string S;
    cin >> N >> 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 + 4] == 'F' || (S[i + 3] == 'T' && S[i + 4] == 'C')) {
                S[i + 3] = 'F'; // Change 'CPC' to 'FPF'
                ++count;
            }
        }
    }

    cout << count << endl;

    return 0;
}