def main():
  N = int(input())
  v = [int(i) for i in input().split()]
  v.sort()
  ans = 0
  for i in range(len(v)-1):
    ans = (ans+v[i+1])/2 if i > 0 else (v[i]+v[i+1])/2


if __name__ == '__main__':
  main()
