#coding: utf-8
##yuki_275

n=int(raw_input())

s=[]
s=map(int,raw_input().split())
ls=list(s)
lsr=ls[:n]

lsr.sort()
if n%2==0:
 print (lsr[n/2-1]+lsr[n/2])/2.0
else:
 print lsr[(n-1)/2]