N = int(input())
B = input().split()
B = list(B)
A = []
for x in range(N):
    A.append(int(B[x]))
for i in range(N):
    min_num = A[i]
    for j in range(i+1, N):
        if min_num > A[j]:
            min_num = A[j]
            num = j
    if min_num != A[i]:
        A[num] = A[i]
        A[i] = min_num
if N % 2 == 0:
    n = N // 2
    print((A[n] + A[n-1]) / 2)
else:
    n = N // 2
    print(A[n])