def format_80(s):
  """
  Split string that is longer than 80 characters to several lines

  Args:
    s (str)

  Returns:
    ss (str): formatted string
  """
  i = 0
  ss = ''
  for x in s:
    ss += x
    i += 1
    if i == 80:
      i = 0
      ss += ' \ \n'
  return ss