(defun rember (a lat)
(cond 
((null lat) nil)
(t (cond 
      ((eq (car lat) a) (cdr lat))
      (t (cons (car lat) (rember a (cdr lat))))))))


(defun minvet (vet)
(cond
( (null (cdr vet)) (car vet) )
( (< (car vet) (car (cdr vet)))
  (minvet (cons (car vet) (cdr (cdr vet))  )) )
(t (minvet (cdr vet)) )     ))   


(defun orderinc (vet)
(setq a (minvet vet))
(cond
((null (cdr vet)) vet)
(t (cons a (orderinc (rember a vet)))))) 


(defun ultelem (list) 
(cond
( (null (cdr list)) (car list) )
(t (ultelem (cdr list)) ))) 

(defun even# (lat)
(cond 
( (null lat) t )
( (null (cdr lat)) nil)
(t (odd# (cdr lat)) ) ))

(defun odd# (lat)
(cond 
( (null lat) nil )
( (null (cdr lat)) t)
(t (even# (cdr lat)) ) )) 

(defun checklat (l)
(cond 
( (null l) t)
(t (and (atom (car l)) (checklat (cdr l)))) ))

(defun firstatom (l)
(setq a (car l))
(cond 
( (null a) nil )
( (atom a) a )
(t (firstatom a)) )) 

(defun tamanho (l) 
(cond
( (null l) 0)
(t (+ 1 (tamanho (cdr l))))))

(defun joinlist (l1 l2)
(cond 
( (null l1) l2 )
( (cons (car l1) (joinlist (cdr l1) l2)))))

(defun separateodd (v1 v2 vet)
(cond
( (null vet) (cons v1 (cons v2 ()) ) )
( (oddp (car vet)) (separateodd (cons (car vet) v1) v2 (cdr vet)))
(t (separateodd v1 (cons (car vet) v2) (cdr vet)))))

(defun testset (lat) 
(cond
( (null lat) t)
( (member (car lat) (cdr lat)) nil)
( t (testset (cdr lat))) ))

(defun median (vet) 
(setq v (orderinc vet))
(setq n (tamanho vet))
(cond 
( (<= n 1) nil )
( (<= n 3) (car v) )
( t (median (remult (cdr v))))  ))

(defun remult (lat) 
(cond
( (null (cdr lat)) nil )
(t (cons (car lat) (remult (cdr lat)) ))))

(defun testset (l) 
(cond
( (not (checklat l)) nil)
( (null l) t )
( (member2 (car l) (cdr l)) nil )
(t (testset (cdr l)))  )) 

(defun member2 (a list) 
(cond 
( (null list) nil )
( (eq a (car list)) t )
(t (member2 a (cdr list)) ) ))