object main extends App {
  val sc = new java.util.Scanner(System.in)
  val itemCount: Int = sc.nextInt
  val items = List.fill(itemCount)(sc.nextInt).map(_.toDouble).sortWith(_.compareTo(_) < 0)
  println(items)
  val ans = items.fold(items(0))((acc, curr) => ( acc + curr ) / 2)
  println(ans)
}