(defun process-string (input-str)
  (let ((result-str "")
        (n (length input-str)))
    ;; パターンを置換
    (dotimes (i n)
      (setf result-str (concatenate 'string result-str (subseq input-str i (1+ i))))
      (when (and (>= (length result-str) 7)
                 (string= (subseq result-str (- (length result-str) 7) (length result-str)) "CPCTCPC"))
        (setf result-str (subseq result-str 0 (- (length result-str) 3)))
        (setf result-str (concatenate 'string result-str "F"))))
    result-str))

(defun count-cpctf (processed-str)
  (let ((count 0)
        (len (length processed-str)))
    (dotimes (i (- len 4))
      (when (string= (subseq processed-str i (+ i 5)) "CPCTF")
        (incf count)))
    count))

(defun main ()
  (let ((n (read))
        (input-str ""))
    (setf input-str (read-line))
    (let ((transformed-string (process-string input-str)))
      (format t "~A~%" (count-cpctf transformed-string)))))

(main)