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 <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
#include <functional>
using namespace std;
using namespace __gnu_pbds;

#define ll long long
#define mk make_pair

template <class key, class cmp = std::less<key>>
using ordered_set = tree<key, null_type, cmp, rb_tree_tag, tree_order_statistics_node_update>;
const ll mod = 1e9 + 7;

/*
    if you have any question about any part of my code,
    please don't shy to ask anytime :)
*/



void solve()
{
    string x;
    cin>>x;
    if(x=="ABC")
    {
        cout<<"ARC"<<endl;
    }
    else
    {
        cout<<"ABC"<<endl;
    }
    
}

int main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    // ll t;
    // cin >> t;

    // while (t--)
    // {
    //     solve();
    // }
    solve();
    return 0;
}