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 C++ (GCC 9.2.1) (judge verdict: Accepted)

#include <stdio.h>
#include <iostream>
#include <math.h>
#include <string>
#include <vector>
#include <algorithm>
#include <iomanip>
#include <queue>
#include <map>

//#include <bits/stdc++.h>
using namespace std;
#define print(x) cout<<(x)<<endl
#define rep(i, n) for(int i = 0; i < (int)n; i++)
#define ll long long int
#define pb push_back

int main() {
  string S;
  cin >> S;

  if(S == "ABC"){
    print("ARC");
  } else {
    print("ABC");
  }

}