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 fr(dt,i,a,b) for(dt i=a;i<b;i++)
#define f0(a,b) for(int i=a;i<b;i++)
#define fn(b,a) for(int i=b;i>a;i--)
#define dbg(x); cout<<"\n"<<#x<<": "<<x;
#define ret return
#define pb push_back
#define pf push_front
#define fastIO(); ios_base::sync_with_stdio(false); cin.tie(NULL);
#define UL9 1000000007
#define UL5 100007
#define INF 1e9+7
#define PI 3.1415926
#define sq(a) (a)*(a)
#define fs first
#define sd second
typedef vector<long long int> vlli;
typedef vector<int> vi;
typedef map<char,int> mci;
typedef long long int lli;  //  e-18 to e18
int main(){
    fastIO();
    string s;
    cin>>s;
    if(s=="ABC") cout<<"ARC\n";
    else cout<<"ABC\n";
    ret 0; 
}