(define (System.out.println x)
  (begin
    (display x)
    (newline)
  )
)

(let (
      (N (read))
      (ls '())
     )
  (let loop(
            (foo (read))
           )
    (if (eof-object? foo)
        (begin (set! ls (sort ls <))
               (if (= (modulo N 2) 0)
                   (System.out.println (exact->inexact (/ (+ (list-ref ls (- (/ N 2) 1)) (list-ref ls (/ N 2))) 2)))
                   (System.out.println (exact->inexact (list-ref ls (- (ceiling (/ N 2)) 1))))
                )
        )
        (begin
          (set! ls (cons foo ls))
          (loop (read))
        )
    )
  )
)