#include<bits/stdc++.h>
using namespace std;

#define ll long long int

int main() {

    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);

    string s;
    cin>>s;
    if(s[1]=='R')
        cout<<"ABC\n";
    else
        cout<<"ARC\n";
    
    return 0;
}