(define (read-node n m) (cond
  [(equal? n empty) empty]
  [(and (= m 0) (node? (node-left n)) (eq? (node-right n) empty)) (make-node (read-node (node-left n) (+ m 1)) (make-node empty empty))]
  [(and (= m 0) (node? (node-right n)) (eq? (node-left n) empty)) (make-node (make-node empty empty) (read-node (node-right n) (+ m 1)))]
  [(node? n) (make-node (read-node (node-left n) m) (read-node (node-right n) m))]
  )
  )