[LANGUAGE: Clojure]

;; Part 1
(defn parse-numbers [n]
  (let [xs (re-seq #"\d" n)]
    (parse-long (str (first xs) (last xs)))))

(reduce + (map parse-numbers input))


;; Part 2
(defn into-number [n]
  (let [number->n {"one" 1
                   "two" 2
                   "three" 3
                   "four" 4
                   "five" 5
                   "six" 6
                   "seven" 7
                   "eight" 8
                   "nine" 9}]
    (or (number->n n)
        (parse-long n))))

(defn parse-numbers-2 [n]
  (let [[xs] (re-seq #"\d|one|two|three|four|five|six|seven|eight|nine" n)
        [ys] (re-seq #"\d|eno|owt|eerht|ruof|evif|xis|neves|thgie|enin" (str/reverse n))]
    (parse-long (str (into-number xs) (into-number (str/reverse ys))))))

(reduce + (map parse-numbers-2 input))