N = int(input())
arr = input()
guzai = arr.split(" ")
guzai_int = [int(i) for i in guzai]

for i in range(1, N):
  guzai_int.sort()
  x = guzai_int.pop(0)
  y = guzai_int.pop(0)
  guzai_int.append((x+y)/2)

print(guzai_int)