#!/usr/bin/guile -s
!#

(use-modules (ice-9 rdelim))

(define (read-lines)
  (let loop ((line (read-line)))
    (if
      (eof-object? line)
      '()
      (cons line (loop (read-line))))))

(define (map list mapper)
  (if
    (null? list)
    '()
    (cons (mapper (car list)) (map (cdr list) mapper))))

(define (reduce list reducer current)
  (if
    (null? list)
    current
    (reduce (cdr list) reducer (reducer current (car list)))))

(define (first-last-combine current rest)
  (if
    (null? current)
    rest
    (if
      (null? rest)
      current
      (cons (car current) (cdr rest)))))

(define (first-last list predicate)
  (if
    (null? list)
    '()
    (first-last-combine
      (if
        (predicate (car list))
        (cons (car list) (cons (car list) '()))
        '())
      (first-last (cdr list) predicate))))

(define (sum numbers) (reduce numbers + 0))

(define (is-numeric-char char) (if (char-numeric? char) #t #f))

(define (solve-line line)
  (
    (lambda (first-last-result) (string->number (list->string first-last-result)))
    (first-last (string->list line) is-numeric-char)))

(define (solve-all lines)
  (sum (map lines solve-line)))

(display (solve-all (read-lines)))