output_description: Print an integer representing the area of the regular dodecagon.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      r
attempt: N = int(input())
  ans = 0
  lst = list(map(int, input().split()))
  slice_lst = lst[: int(N / 2)]
  for i, k in enumerate(reversed(slice_lst)):
      sub_lst = lst[len(slice_lst) - i - 1 : len(lst) : len(slice_lst) - i]
      if k != sum(sub_lst) % 2:
          if k == 0:
              lst[len(slice_lst) - i - 1] = 1
          else:
              ans = -1
              break
  
  if ans == -1:
      print(ans)
  else:
      ans_lst = []
      for i, k in enumerate(lst):
          if k == 1:
              ans_lst.append(str(i + 1))
      print(len(ans_lst))
      result = " ".join(ans_lst)
      print(result)
  
problem_description: Statement
  
  It is known that the area of a regular dodecagon inscribed in a circle of
  radius a is 3a^2.
  
  Given an integer r, find the area of a regular dodecagon inscribed in a circle
  of radius r.
samples: [{"input": "4", "output": "48\n    \n\nThe area of the regular dodecagon is 3 \\times 4^2 = 48.\n\n* * *"}, {"input": "15", "output": "675\n    \n\n* * *"}, {"input": "80", "output": "19200"}]