(define (odd_word_problem words)
   (letrec ((odd (lambda (s out)
               (let loop ((s s) (l '()))
                  (cond
                     ((null? s)
                        out)
                     ((pair? s)
                        (if (<= #\a (car s) #\z)
                           (loop (cdr s) (cons (car s) l))
                           (even (cdr s) (cons (cons (reverse l) (car s)) out))))
                     (else
                        (loop (s) l))))))
            (even (lambda (s out)
               (let loop ((s s) (l '()))
                  (cond
                     ((null? s)
                        out)
                     ((pair? s)
                        (if (<= #\a (car s) #\z)
                           (loop (cdr s) (cons (car s) l))
                           (odd (cdr s) (cons (cons l (car s)) out))))
                     (else
                        (loop (s) l)))))))
      (for-each (lambda (p)
                  (display (runes->string (car p)))
                  (display (string (cdr p))))
         (reverse
            (odd (str-iter words) '()))))
      (print))
(odd_word_problem "what,is,the;meaning,of:life.")
(odd_word_problem "we,are;not,in,kansas;any,more.")