/**
*    created: 03.05.2020 21:00:14
**/

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

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