import java.util.*
 
fun main(args: Array<String>) {
  var a = readLine()!!.toInt()-1
  var num = readLine()!!.split(" ").map{ it -> it.toInt() }.toMutableList()
  var counter = 0
  
  num.sort()
  var dp = num[0]

  
  for (i in 1..a) {
    dp = (dp + num[i]) /2
  }
  println(dp)
}