S = eval(input())

if(S == 'ABC'):

  print('ARC')

elif(S == 'ARC'):

  print('ABC')

else:

  pass
S = eval(input())

if S == 'ABC':

  print('ARC')

else:

  print('ABC')
S = eval(input())
if S == "ABC":
    print("ARC")
elif S == "ARC":
    print("ABC")
else:
    pass

S = eval(input())
if S == "ABC":
    print("ARC")
else:
    print("ABC")

-elif S == "ARC": +else: -else: -    pass