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)

import sys
import math  # noqa
import bisect  # noqa
import queue  # noqa


def input():
    return sys.stdin.readline().rstrip()


def main():
    S = input()

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


if __name__ == '__main__':
    main()