(io.input "input")

(var sum1 0)
(var sum2 0)
(each [line (io.lines)]
  (let [pattern "(%d+)-(%d+),(%d+)-(%d+)"
    [ri1 rf1 ri2 rf2] 
    (icollect [_ n (-> line (string.match pattern) (table.pack) (ipairs))]
; (-> ...) equivalent to:
;        (ipairs (table.pack (string.match line pattern)))] 
      (tonumber n))]
      (when (or (and (>= ri1 ri2) (<= rf1 rf2))
                (and (>= ri2 ri1) (<= rf2 rf1)))
        (set sum1 (+ sum1 1)))
      (when (and (>= rf1 ri2) (<= ri1 rf2)) 
        (set sum2 (+ sum2 1)))))

(print "part 1" sum1)
(print "part 2" sum2)