output_description: Print the string representing the type of the contest held this week.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      S
attempt: import glob
  
  # 問題ごとのディレクトリのトップからの相対パス
  REL_PATH = "ABC\\166\\A"
  
  # テスト用ファイル置き場のトップ
  TOP_PATH = "C:\\AtCoder"
  
  
  class Common:
  
      problem = []
      index = 0
  
      def __init__(self, rel_path):
          self.rel_path = rel_path
  
      def initialize(self, path):
          file = open(path)
          self.problem = file.readlines()
          self.index = 0
          return
  
      def input_data(self):
          try:
              IS_TEST
              self.index += 1
              return self.problem[self.index - 1]
  
          except NameError:
              return input()
  
      def resolve(self):
          pass
  
      def exec_resolve(self):
          try:
              IS_TEST
              for path in glob.glob(TOP_PATH + "\\" + self.rel_path + "/*.txt"):
                  print("Test: " + path)
                  self.initialize(path)
                  self.resolve()
                  print("\n\n")
          except NameError:
              self.resolve()
  
  
  class Solver(Common):
  
      def resolve(self):
  
          S = map(int, self.input_data().split())
  
          if S == "ABC":
              print("ARC")
          else:
              print("ABC")
  
  
  solver = Solver(REL_PATH)
  solver.exec_resolve()
  
problem_description: Statement
  
  AtCoder Inc. holds a contest every Saturday.
  
  There are two types of contests called ABC and ARC, and just one of them is
  held at a time.
  
  The company holds these two types of contests alternately: an ARC follows an
  ABC and vice versa.
  
  Given a string S representing the type of the contest held last week, print
  the string representing the type of the contest held this week.
samples: [{"input": "ABC", "output": "ARC\n    \n\nThey held an ABC last week, so they will hold an ARC this week."}]