#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int,int> P;
ll const mod = 1e9+7;

int main() {
    string S;
    string abc = "ABC", arc = "ARC";
    cin >> S;
    if (S == abc)   cout << arc << endl;
    else cout << abc << endl;
}