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 <vector>
#include <map>
#include <bitset>
#include <algorithm>
#include <string>
#include <queue>
#include <stack>
#include <cmath>
#include <set>
#include <list>
#include <sstream>

#define ll long long
#define ld long double
#define ull unsigned long long
using namespace std;

const ll mod = 1000000007;
const ll inf = 9223372036854775803;
const int maxN = 300005;

int main() {
    cin.tie(0);
    ios_base::sync_with_stdio(false);
    string s;
    cin >> s;
    if (s == "ABC") {
        cout << "ARC";
    } else {
        cout << "ABC";
    }
    return 0;
}