#include <bits/stdc++.h>
using namespace std;

int main() {
    int n;
    string s;
    cin >> n >> s;
    string t = "";
    int i = 0;
    while (i < n) {
        if (s[i] == 'C' && i + 6 < n && s.substr(i, 7) == "CPCTCPC") {
            t += "CPCTF";
            i += 7;
        } else {
            t += s[i];
            i++;
        }
    }
    int ans = 0;
    for (int i = 0; i <= (int)t.size() - 5; i++) {
        if (t.substr(i, 5) == "CPCTF") {
            ans++;
        }
    }
    cout << ans << endl;
}