(defun count-tf (ql hmtf)
  (cond
   ( (and (null ql) (= hmtf 0))
     t )
   ( (and (null ql) (not (= hmtf 0)))
     nil )
   ( (eq (car ql) 'tf)
     (count-tf (cdr ql) (- hmtf 1)) )
   ( t
     (count-tf (cdr ql) hmtf) )
  )
)

(defun test-count-tf ()
 (setq rtn (list
  (count-tf '() 0)		; Expect t
  (count-tf '(tf) 1)		; Expect t
  (count-tf '(tf tf) 2)		; Expect t
  (count-tf '(tf tf tf) 3)	; Expect t
  (count-tf '(tf x tf tf) 3)	; Expect t
  (count-tf '(tf tf x tf) 3)	; Expect t
  (count-tf '(x tf tf x tf x) 3); Expect t
  (count-tf '(x tf tf x tf x x x x x x x x x x x x x x tf) 4); Expect t

  (count-tf '() 1)		; Expect nil
  (count-tf '(tf) 2)		; Expect nil
  (count-tf '(tf tf) 3)		; Expect nil
  (count-tf '(tf tf tf) 4)	; Expect nil
  (count-tf '(tf x tf tf) 4)	; Expect nil
  (count-tf '(tf tf x tf) 4)	; Expect nil
  (count-tf '(x tf tf x tf x) 4); Expect nil

  (count-tf '() -1)		; Expect nil
  (count-tf '(tf) 0)		; Expect nil
  (count-tf '(tf tf) 1)		; Expect nil
  (count-tf '(tf tf tf) 2)	; Expect nil
  (count-tf '(tf x tf tf) 2)	; Expect nil
  (count-tf '(tf tf x tf) 2)	; Expect nil
  (count-tf '(x tf tf x tf x) 2); Expect nil

  (count-tf '() 1)		; Expect nil
  (count-tf '() 2)		; Expect nil
  (count-tf '() 100000)		; Expect nil
  (count-tf '(tf) 0)		; Expect nil
  (count-tf '(tf) 2)		; Expect nil
 ))
)

(test-count-tf)