#include <bits/stdc++.h>
#include <vector>
#include <string>
#include <stdio.h>
#include <math.h>
#include <cstdlib>
#include <iostream>
#include <cstdlib>
#include <algorithm>
using namespace std;
using ll = long long;

int main()
{
    string s;
    cin>>s;
    if(s[1]=='B')
    {
        cout<<"ARC";
    }
    else
                cout<<"ABC";

    return 0;
}
