same-parity 10

(define (same-parity? m n)
  (= (remainder m 2)
     (remainder n 2)))

(define (same-parity fst . lst)
  (define (parity-list ls res)
    (cond ((null? ls) (reverse res))
          ((same-parity? fst (car ls))
           (parity-list (cdr ls) (cons (car ls) res)))
          (else
           (parity-list (cdr ls) res))))
  (cons fst (parity-list lst null)))