N = int(input())
A = list(map(int, input().split()))
A = sorted(A)
a,b = 0,0
if N % 2 == 0:
    a = N / 2
    b = a - 1
    ans = (A[int(a)] + A[int(b)]) / 2
    print(ans)
else:
    b = N / 2
    print(A[int(b)])