import java.util.*

fun main(args:Array<String>){
    val n = readLine()!!.toInt()
    val a = readLine()!!.split(" ").map{it.toDouble()}
    val b = a.sorted()
    println(b)
    var ans : Double = b[0]
    for(i in 1 until n) ans = (ans + b[i]) / 2
    println("%.10f".format(ans))
}