(define (v s)
  ((if (eq? (first s) 'c)
       (letrec ((init (accept 'c loop))
		(loop (accept 'a loop
			      'd loop
			      'r end))
		(end (accept 'r end)))
	 init)
       (letrec ((see0 (accept '0 see1))
		(see1 (accept '1 see0)))
	 see0))
   s))