(with-temp-buffer
     (insert-file-contents "input")
     (goto-char (point-min))
     (replace-regexp "^" "\"")
     (goto-char (point-min))
     (replace-regexp "$" "\"")
     (goto-char (point-min))
     (insert "(setq data '(")
     (goto-char (point-max))
     (insert "))")
     (eval-buffer))

(setq height (length data)
      width (length (car data)))

(setq antennas (-mapcat #'identity (-map-indexed (lambda (y ll) (-map-indexed (lambda (x el) (list el (list  x y)))  ll) )
                               (-map (lambda (str)
                                       (-map #'string-to-char (split-string str "\\|.+" t)))
                                     data))))

(setq positions (-map (lambda (antenna) (-map #'cadr (-filter (lambda (a) (eq (car a) antenna)) antennas)))
        (-remove-item 46 (-distinct  (-map #'car antennas)))))

(defun diff (l ll)
  (op-lists #'- l ll))

(defun op-lists (op l ll)
  (-map (lambda (pair) (funcall op (car pair) (cadr pair))) (-zip-lists l ll)))

(defun diff-positions (l)
  (-filter #'valid-position (-mapcat (lambda (pair) (-map (lambda (pp) (diff pair (diff pp pair))) (-remove-item pair l))) l)))

(defun valid-position (pair)
  (and (> (car pair) -1) (< (car pair) width) (> (cadr pair) -1) (< (cadr pair) height)))

(defun gcd (n m)
  (cond ((< (abs  n) (abs m)) (gcd m n))
        ((= m 0) n)
        (t (gcd m (% n m)))))

(length  (-distinct (-mapcat #'diff-positions positions)))

(defun generate-line (origin delta)
  (let* ((ggg (gcd (abs (car delta)) (abs (cadr delta))))
        (del (--map (/ it ggg) delta)))
    (-unfold (lambda (x) (when (valid-position x) (cons x (op-lists '+ x del)))) origin)))

(defun line-positions (l)
  (-filter #'valid-position
           (-mapcat (lambda (pair)
                      (-mapcat (lambda (pp) (generate-line pair (diff pp pair))) (-remove-item pair l)))
                    l)))
(length  (-distinct (-mapcat #'line-positions positions)))