S=eval(input())

if S=="ABC":

    print("ARC")

if S=="ARC":

    print("ABC")
A=eval(input())

if A=="ABC":

    print("ARC")

if A=="ARC":

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

A = eval(input())
if A == "ABC":
    print("ARC")
if A == "ARC":
    print("ABC")

-S = eval(input()) -if S == "ABC": +A = eval(input()) +if A == "ABC": -if S == "ARC": +if A == "ARC":