#coding: UTF-8

import sys
import re
import itertools
from collections import deque

### defs ###


### main ###
N = int(input())
A = list(map(int,input().split()))
A.sort()
if(N%2==0):
	a1 = A[N//2-1]
	a2 = A[N//2]
	print((a1+a2)/2)
else:
	print(A[N//2])