output_description: Print the name of the next contest rated for Takahashi (`ABC`, `ARC` or
  `AGC`).
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      R
attempt: #-*-coding:utf-8-*-
  
  def main():
      r = int(input())
      if r < 2000:
          print('ABC')
      elif r >= 1200 ans r < 2800:
          print('ARC')
      else:
          print('AGC')
  
  if __name__ == '__main__':
      main()
problem_description: Statement
  
  A programming competition site _AtCode_ regularly holds programming contests.
  
  The next contest on AtCode is called ABC, which is rated for contestants with
  ratings less than 1200.
  
  The contest after the ABC is called ARC, which is rated for contestants with
  ratings less than 2800.
  
  The contest after the ARC is called AGC, which is rated for all contestants.
  
  Takahashi's rating on AtCode is R. What is the next contest rated for him?
samples: [{"input": "1199", "output": "ABC\n    \n\n1199 is less than 1200, so ABC will be rated.\n\n* * *"}, {"input": "1200", "output": "ARC\n    \n\n1200 is not less than 1200 and ABC will be unrated, but it is less than 2800\nand ARC will be rated.\n\n* * *"}, {"input": "4208", "output": "AGC"}]