(declaim (inline println))
(defun println (obj &optional (stream *standard-output*))
  (let ((*read-default-float-format* 'double-float))
    (prog1 obj
      (princ obj stream)
      (terpri stream))))

(defun ok (xs)
  (sb-int:named-let rec ((xs xs)
                         (c #\a))
    (or (null xs)
        (and (char<= c (first xs))
             (rec (rest xs)
                  (first xs))))))

(defun get-l-and-r (xs)
  (when (ok xs)
    (list (length xs)
          (first (sort (copy-seq xs) #'char<))
          (first (sort (copy-seq xs) #'char>)))))

(define-modify-macro maxf (var) max)

(defun char->int (c)
  (- (char-code c)
     (char-code #\a)))

(defun main ()
  (let* ((n (read))
         (ss (sort (remove-if #'null (mapcar #'get-l-and-r (loop repeat n collect (concatenate 'list (read-line))))) #'(lambda (xs ys)
                                                                                                                         (if (char= (second xs) (second ys))
                                                                                                                             (char< (third xs) (third ys))
                                                                                                                             (char< (second xs) (second ys))))))
         (ys (make-array 26 :initial-element nil)))
    (loop for (cnt l r) in ss
          do (push (list cnt (char->int r))
                   (aref ys (char->int l))))
    (let ((dp (make-array 26 :initial-element 0)))
      (dotimes (l 26)
        (loop for (cnt r) in (aref ys l)
              do (loop for idx from r below 26
                       do (maxf (aref dp idx)
                                (+ (aref dp l)
                                   cnt)))))
      (println (reduce #'max dp)))))

#-swank (main)