N = int(input())
A = input()

S = list(A)         # リストに格納
while " " in S:     # " "の要素削除
    S.remove(" ")

S2 = sorted(S)

if N % 2 == 1:
    i = N/2 + 1
    ans = int(S2[i])
else:
    i = int(N/2)
    ans = (int(S2[i]) + int(S2[i-1])) / 2

print(ans)