text: """
  Champernowne's constant
  Problem 40
  An irrational decimal fraction is created by concatenating the positive
  integers:
  
  0.123456789101112131415161718192021...
  
  It can be seen that the 12th digit of the fractional part is 1.
  
  If dn represents the nth digit of the fractional part, find the value of the
  following expression.
  
  d1 × d10 × d100 × d1000 × d10000 × d100000 × d1000000
  """
  
  
  def solution():
      """Returns
  
      >>> solution()
      210
      """
      constant = []
      i = 1
  
      while len(constant) < 1e6:
          constant.append(str(i))
          i += 1
  
      constant = "".join(constant)
  
      return (
          int(constant[0])
          * int(constant[9])
          * int(constant[99])
          * int(constant[999])
          * int(constant[9999])
          * int(constant[99999])
          * int(constant[999999])
      )
  
  
  if __name__ == "__main__":
      print(solution())
  