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 <iostream>
#include <iterator>
#include <algorithm>
#include <map>
#include <queue>
#include <set>
#include <string>
#include <cstring>
#include <stack>
#include <vector>
#include <list>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <limits>
#include <utility>
#define EPS (1e-10)
#define REP(i,n) for(int i=0;i<n;i++)
#define equals(a,b) (fabs((a) - (b)) < EPS)
#define ll long long
using namespace std;

//typedef pair<int,int> P;
//const ll MOD = 1000000007;
//const ll INF = 100000000;

const int max_N = 100000;
string S;

//stack<int> stack;
//queue<int> que;
//priority_queue<int> pque;
//set<int> s; set<int>::iterator ite;
//multiset<int> ms; multiset<int>::iterator ite;
//map<int, int> m; map<int, int>::iterator ite;
//multimap<int, int> mm; multimap<int, int>::iterator ite;

//int dp[][];
//int dx[4] = {1, 0, -1, 0}; int dy[4] = {0, -1, 0, 1};
//int dx[8] = {1, 1, 1, 0, -1, -1, -1, 0};
//int dy[8] = {0, -1, -1, -1, 0, 1, 1, 1};

void solve() {
  if(S == "ABC") printf("ARC\n");
  else printf("ABC\n");
}

int main(int argc, char const *argv[]) {

  cin >> S;

  solve();
  return 0;
}