fun main(args: Array<String>) {
    p746()
}

fun p746() {
    val n = readLine()!!.toInt()
    val aList = readLine()!!.split(' ').map { it.toDouble() }

    val sorted = aList.sorted()
    val answer = (sorted[(n - 1) / 2] + sorted[n / 2]) / 2

    println(answer)
}