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: Wrong Answer)

#include <bits/stdc++.h>
using namespace std;
using llong = long long;
#define rep(i,N) for (int i = 0; i < N; i++)

const llong MOD = 1e9+7;
const llong inf = 1<<30;

int main() {
    string S; cin >> S;
    string word[2] = {"ABC", "ARC"};
    string res;
    if (S == word[0]) {
        res = word[1];
    }else{
        res == word[0];
    }
    cout << res << endl;
    return 0;
}