(defn compute_distance [left right]
  (if
    (not (=
      (length left)
      (length right)))
    (return @[]))

  (var output 0)

  (def sorted_left (sort left))
  (def sorted_right (sort right))

  (var i (- (length sorted_left) 1))
  (while (>= i 0)
    (set output (+ output
      (math/abs (- (get sorted_left i) (get sorted_right i)))))
    (-- i))

  output)

(defn getnums [input]
  (def output (array/new 2))
  (def str (string/split " " (string/trim input)))
  (var i 0)
  (each item str
    (if (not (= item ""))
      (do
        (set (output i) (scan-number item))
        (++ i))))
  output)

(defn read_data [filename]
  (def left @[])
  (def right @[])
  (var index 0)

  (with [f (file/open filename)]
    (while true
      (var l (file/read f :line))
      (if l
        (do
          (def line_data (getnums l))
          (set (left index) (get line_data 0))
          (set (right index) (get line_data 1))
          (++ index))
        (break))))
  @[left right])

(defn main [script filename]
  (def input_arrays (read_data filename))
  (def left (get input_arrays 0))
  (def right (get input_arrays 1))
  (def distance (compute_distance left right))
  (pp distance))