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())
  A = list(map(int, input().split()))
  box = [0] * n
  for i in range(n - 1, -1, -1):
      if n // (i + 1) <= 1 and A[i] == 1:
          box[i] = 1
      elif n // (i + 1) <= 1 and A[i] == 0:
          pass
      elif n // (i + 1) > 1:
          if A[i] == sum(box[2 * (i + 1) - 1 :: (i + 1)]) % 2:
              pass
          elif A[i] != sum(box[2 * (i + 1) - 1 :: (i + 1)]) % 2:
              box[i] = 1
  ans = ""
  for i in range(n):
      if box[i] == 1:
          ans += str(A[i]) + " "
  if sum(box) % 2 == A[0]:
      print(sum(box))
      print(ans)
  else:
      print("-1")
  
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"}]