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>
#define FIO ios::sync_with_stdio(0), cin.tie(0), cout.tie(0)
#define FOR(a,b,c) for(int a = (b); a <= (c); a++)
#define RFOR(a,b,c) for(int a = (b); a >= (c); a--)
#define all(x) (x).begin(), (x).end()
#define vi vector <int>
#define vvi vector <vi>
#define ll long long
#define vll vector <ll>
#define vvl vector <vll>
#define pii pair<int,int>
#define pll pair<ll,ll>
#define eb emplace_back
#define ep emplace
#define fs first
#define sd second
#define mod 998244353
#define EPS 1e-9
#define tc int t; cin >> t; while(t--)
using namespace std;

int main() {
    FIO;
    string s; cin >> s;
    if(s == "ABC") cout << "ARC" << '\n';
    else cout << "ABC" << '\n';
    return 0;
}