#include <iostream>
#include <vector>
#include <set>
#include <string>
#include <algorithm>

using namespace std;


int main() {
    int n; string s;
    cin >> n >> s;

    while (s.find("CPCTCPC") != string::npos){
        s.replace(s.find("CPCTCPC"), 7, "CPCTF");
    }

    int count = 0;
    for (int i = 0; i < s.size(); i++) {
        if(s.find("CPCTF") != string::npos){
            count++;
        }
    }

    cout << count;
    //cout << s;
    return 0;
}