N = int(input())
A = list(map(int,input().split(' ')))
A.sort()

if N % 2 > 0:
    n = N // 2
    print(A[n])
else:
    ind_1 = N // 2 - 1
    ind_2 = N // 2
    a = A[ind_1:ind_2 + 1]
    a_sum = sum(a)
    print(a_sum / 2)