(import (scheme base)
        (scheme char)
        (scheme file)
        (scheme process-context)
        (scheme write))

(define (max-joltage line batteries)
  (let ((lst (map digit-value (string->list line))))
    (let loop ((req-tail-length (- batteries 1))
               (lst lst)
               (sum 0))
      (if (negative? req-tail-length)
          sum
          ;; this is O^one million at least
          (let ((m (memq (apply max (reverse (list-tail (reverse lst) req-tail-length))) lst)))
            (loop (- req-tail-length 1) (cdr m) (+ (* sum 10) (car m))))))))

(define (part file batteries)
  (with-input-from-file file
    (lambda ()
      (let loop ((line (read-line))
                 (sum 0))
        (if (eof-object? line)
            (begin
              (display (number->string sum))
              (newline))
            (loop (read-line) (+ sum (max-joltage line batteries))))))))

(for-each (lambda (file) (part file 2)) (cdr (command-line)))
(for-each (lambda (file) (part file 12)) (cdr (command-line)))