(defun main (&rest argv)
  (declare (ignorable argv))
  (let* ((n (read))
         (f (make-array (list n n) :element-type 'integer))
         (s 0)
         (dp (make-array (ash 1 n) :element-type 'integer :initial-element -1)))
    (dotimes (i n)
      (dotimes (j n)
        (setf (aref f i j) (read))))
    (setf (aref dp 0) 0)
    (dotimes (i (ash 1 n))
      (when (>= (aref dp i) 0)
            (dotimes (j n)
              (when (zerop (logand i (ash 1 j)))
                    (setq s j)
                    (return)))
            (loop for j from (1+ s) below n
                  when (zerop (logand i (ash 1 j)))
                    do (setf (aref dp (logior i (ash 1 s) (ash 1 j))) (max (aref dp (logior i (ash 1 s) (ash 1 j))) (+ (aref dp i) (aref f s j)))))))
    (format t "~d~%" (aref dp (1- (ash 1 n))))))

(main)