import numpy as np

num = int(input())
data = np.array([int(x) for x in input().split(" ")])

data2 = sorted(data)
if num % 2 == 0:
    output = (data2[int(num/2)-1] + data2[int(num/2)])/2.0
else:
    output = data2[int(num/2)]

print(output)