import sys

read = sys.stdin.buffer.read

readline = sys.stdin.buffer.readline

readlines = sys.stdin.buffer.readlines

sys.setrecursionlimit(10 ** 7)



s = readline().rstrip().decode()

if s[1] == 'B':

    print('ARC')

else:

    print('ABC')

import sys

read = sys.stdin.buffer.read

readline = sys.stdin.buffer.readline

readlines = sys.stdin.buffer.readlines

sys.setrecursionlimit(10 ** 7)



s = read().rstrip().decode()

if s[1] == 'B':

    print('ARC')

else:

    print('ABC')

import sys

read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines
sys.setrecursionlimit(10**7)
s = readline().rstrip().decode()
if s[1] == "B":
    print("ARC")
else:
    print("ABC")

import sys

read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines
sys.setrecursionlimit(10**7)
s = read().rstrip().decode()
if s[1] == "B":
    print("ARC")
else:
    print("ABC")

-s = readline().rstrip().decode() +s = read().rstrip().decode()