n = input()
N = int(n)
f = input()
s_f = f.split()
list_f = [int(v) for v in s_f]
list_s = sorted(list_f)
if N % 2 == 1:
    a = (N - 1) // 2
    print(list_s[a])
else:
    a = N // 2
    b = list_s[a-1]
    c = list_s[a]
    d = (b + c) / 2
    print(d)