#include <iostream>
#include <vector>
#include<algorithm>
//#include <string>
//#include <cassert>
//#include <cmath>
//#include <limits>
using namespace std;

int N;
string S;


int solve() {


    return 1;
}

int main() {

    cin >> S;

    auto ans = "ABC";
    if (S == "ABC") ans = "ARC";


    cout << ans << endl;

    return 0;
}