n = int(input())
l = list(map(int,input().split()))
for i in range(n-1):
    for j in range(n-i-1):
        if l[j] > l[j+1]:
            tem = l[j]
            l[j] = l[j+1]
            l[j+1] = tem
if n % 2 == 0:
    print((l[n//2-1]+l[n//2])/2)
else:
    print(l[n-1//2])