(defvar N)
(setq N (parse-integer (read-line)))

(defparameter item (make-array 11 :initial-element 0))
;テスト
(loop for line = (read-line nil nil) while line do
 (setq line (concatenate 'string "(" line ")" ))
 (setq line (read-from-string line))
 (loop for i from 0 to 2 do
  ;(print (nth i line))
  (incf (aref item (nth i line)))
 )
 ;(print item )
)

(defparameter sum 0)
(loop for i from 1 to 10 do
 (setq sum (+ sum (floor (aref item i) 2)))
 (setf (aref item i) (mod (aref item i) 2) )
 ;(print item)
)

(defparameter sum2 0)
(loop for i from 1 to 10 do
 (setq sum2 (+ sum2 (aref item i)))
 )

(setq sum (+ sum (floor sum2 4)))
;(print sum)
(format 't "~d~%" sum)