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 Python (3.8.2) (judge verdict: Accepted)

#!/usr/bin/env python3
import collections
import itertools as it
import math
#import numpy as np
 
s  = input()
#  = int(input())
#  = map(int, input().split())
#  = list(map(int, input().split()))
#  = [int(input()) for i in range(N)]
#
# c = collections.Counter()

print('ABC' if s == 'ARC' else 'ARC')