# -*- coding: utf-8 -*-
import math

n = int(input())
a = [int(i) for i in input().split()]
s = sorted(a)

result = 0
if n % 2 == 0:
    x = (n - 1) / 2    
    lower = math.floor(x)
    upper = math.ceil(x)
    result = (s[lower] + s[upper]) / 2
else:
    x = (n - 1) // 2
    result = s[x]
print(round(result, 1))