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>
using namespace std;

#define watch(x) cout << (#x) << " is " << (x) << endl
#define fr(i,n) for(int i=0; i<n; i++)
#define rep(i, st, en) for(int i=st; i<=en; i++)
#define repn(i, st, en) for(int i=st; i>=en; i--)
#define sq(a) (a*a)
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
ll mod = 1e9+7;


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

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

    ll t = 1;
    //  cin>>t;
    while(t--){
        solve();
    }

    return 0;
}