def main():
    N = int(input())
    A = tuple(map(int, input().split()))

    a = sorted(A)
    l = len(a)
    if l & 1:
        ans = a[l // 2]
    else:
        s = l // 2 - 1
        e = s * -1
        ans = sum(a[s:e]) / 2

    print(ans)

main()