#lang sicp

(define (same-parity fst . lst)
  (define (same-parity-aux parity lst)
    (cond ((null? lst) '())
          ((equal? parity (even? (car lst)))
           (cons (car lst) (same-parity-aux parity (cdr lst))))
          (else (same-parity-aux parity (cdr lst)))))
  (same-parity-aux (even? fst)
                   (cons fst lst)))