(asdf:load-system :adventofcode2020)
(in-package #:adventofcode2020)
-(named-readtables:in-readtable fn-reader)
+(named-readtables:in-readtable :adventofcode2020)
(defun joltage-distribution (ratings)
(let* ((extended (append '(0) ratings (mapcar λ(+ 3 _) (last ratings)))))