Problem:
Score : 100 points

Problem 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.

Constraints

S is ABC or ARC.

Input

Input is given from Standard Input in the following format:

S

Output

Print the string representing the type of the contest held this week.

Sample Input 1

ABC

Sample Output 1

ARC

They held an ABC last week, so they will hold an ARC this week.

Solution in PyPy3 (7.3.0) (judge verdict: Accepted)

from sys import stdin
from sys import setrecursionlimit
from collections import Counter, deque, defaultdict
from math import floor, ceil
from bisect import bisect_left
setrecursionlimit(100000)

INF = int(1e10)
MOD = int(1e9 + 7)

def input():
    return stdin.readline()[:-1]

def main():
    from builtins import int, map
    S = input()
    if S == 'ABC':
        print("ARC")
    else:
        print("ABC")

if __name__ == '__main__':
    main()