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)

import sys
input = sys.stdin.readline

#n = int(input())
#l = list(map(int, input().split()))
'''
A=[]
B=[]
for i in range():
    a, b = map(int, input().split())
    A.append(a)
    B.append(b)'''

s=input().rstrip("\n")
if s=="ABC":
    print("ARC")
else:
    print("ABC")