n = int(input())
a_list = list(map(int,input().split()))
a_list.sort()
if n % 2 == 1:
    print(a_list[(n+1)//2 - 1])
else:
    m1 = a_list[n//2 - 1]
    m2 = a_list[n//2]
    print((m1+m2) / 2)