package main

import (
	"fmt"
	"sort"
)

func scan() (int, []int) {
	var N int
	fmt.Scan(&N)
	var A []int
	for i := 0; i < N; i++ {
		var a int
		fmt.Scan(&a)
		A = append(A, a)
	}
	return N, A
}

func main() {
	N, A := scan()
	// N := 6
	// A := []int{1, 2, 3, 4, 5, 6}
	var ans float64
	sort.IntSlice(A).Sort()

	if N%2 == 1 {
		ans = float64(A[N/2])
	} else {
		ans = float64(A[N/2-1]+A[N/2]) / 2
	}
	fmt.Printf("%.1f", ans)
}