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()

ans = {'ABC': 'ARC', 'ARC': 'ABC'}

print((ans[s]))

def main():

    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()

    check = {'ABC': 'ARC', 'ARC': 'ABC'}

    print((check[s]))





if __name__ == '__main__':

    main()

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()
ans = {"ABC": "ARC", "ARC": "ABC"}
print((ans[s]))

def main():
    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()
    check = {"ABC": "ARC", "ARC": "ABC"}
    print((check[s]))


if __name__ == "__main__":
    main()

-import sys +def main(): +    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() -ans = {"ABC": "ARC", "ARC": "ABC"} -print((ans[s])) +    read = sys.stdin.buffer.read +    readline = sys.stdin.buffer.readline +    readlines = sys.stdin.buffer.readlines +    sys.setrecursionlimit(10**7) +    s = readline().rstrip().decode() +    check = {"ABC": "ARC", "ARC": "ABC"} +    print((check[s])) + + +if __name__ == "__main__": +    main()