text: # (c) Simon Liedtke <liedtke.simon@googlemail.com> under the ISC license.
  # See COPYING for more details.
  
  
  import sys
  
  
  def sum_of_squares(n):
      return n * (n + 1) * (2 * n + 1) / 6
  
  
  def square_of_sums(n):
      return (n * (n + 1) / 2) ** 2
  
  
  def main(x):
      return square_of_sums(x) - sum_of_squares(x)
  
  
  if __name__ == '__main__':
      try:
          x = int(sys.argv[1])
      except (IndexError, ValueError):
          x = 100
      print(main(x))
  