#!/usr/bin/python
# -*- coding: utf-8 -*-
import math

N = int(raw_input())
array = map(int, raw_input().split())
array.sort()

if N % 2 != 0:
       	print array[int(math.floor(N / 2.0))]
else:
       	print  (array[N / 2] + array[N / 2 - 1 ] ) / 2.0