def ip():return int(input())
def mp():return map(int, input().split())
def lmp():return list(map(int, input().split()))
# No.275 中央値を求めよ
n = ip()
A = lmp()
A.sort()
if n % 2 == 1:
  print(A[n//2])
else:
  print((A[n//2-1] + A[n//2]) / 2)