(define test (lambda (ls) (if (eq? (length ls) (expt 2 (length (all-memb (apply append ls) ())))) 'good 'bad))) (define all-memb (lambda (ls acc) (if (null? ls) acc (if (member (car ls) acc) (all-memb (cdr ls) acc) (all-memb (cdr ls) (cons (car ls) acc))))))