old_contents: def print_rangoli(size):
      pass
      # your code goes here
  
  if __name__ == '__main__':
      n = int(input())
      print_rangoli(n)
  
new_contents: import string
  
  class Rangoli:
  
      DASH = "-"
      ALPHABET = string.ascii_lowercase
      def __init__(self, size):
          self.size = size
          self.num_lines = self.size * 2 - 1
          self.line_length = self.num_lines * 2 - 1
          self.middle_line_num = (self.num_lines - 1) // 2
  
      def __str__(self):
          return "\n".join([self.line(line_number) for line_number in range(0, self.num_lines)])
  
      def line(self, line_number):
          return self.center_text(self.pattern(line_number))
  
      def pattern(self, line_number):
          num_lines_away_from_middle = abs(self.middle_line_num - line_number)
          pattern = ""
          for i in range(self.middle_line_num, num_lines_away_from_middle, -1):
              pattern += self.ALPHABET[i] + self.DASH
  
          pattern += self.ALPHABET[num_lines_away_from_middle]
  
          for i in range(num_lines_away_from_middle + 1, self.middle_line_num + 1):
              pattern += self.DASH + self.ALPHABET[i]
  
          return pattern
  
  
      def center_text(self, text):
          return '{:{fill}^{line_length}}'.format(text, fill=self.DASH, line_length=self.line_length)
  
  
  def print_rangoli(size):
      rangoli = Rangoli(size)
      print(rangoli)
  
  if __name__ == '__main__':
      n = int(input())
      print_rangoli(n)
  
subject: Solve rangoli