(letrec* ((n (string->number (read-line)))
          (r (lambda (n a)
                     (if (zero? n)
                         (reverse a)
                         (r (- n 1) 
                            (cons (map string->number 
                                       (string-split (read-line) " "))
                                  a)))))
          (i (r n '()))
          (v (rlet1 v
                    (make-vector 10 0)
                    (for-each (lambda (x)
                                      (for-each (lambda (y)
                                                        (set! (~ v (- y 1)) 
                                                              (+ (~ v (- y 1)) 1)))
                                                x))
                              i))))
         (print 
           ((rec (c n q r) 
                 (if (negative? n)
                     (begin 
                        (+ (apply + q)
                           (quotient (apply + r) 4)))
                     (c (- n 1)
                        (cons (quotient (~ v n) 2) q)
                        (cons (remainder (~ v n) 2) r))))
            9 '() '())))