#include <bits/stdc++.h>
using namespace std;
	
int main() {
 
  string S;
  cin >> S;
  
 /* for　(int i = 0; i < (N−1)/4; i++) {
	  //a[i] = S.at(i);
	  a[(N−1)/2-1-i] = S.at(i);
	  a[(N+3)/2-1+i] = S.at(i);
	  a[   N   -1-i] = S.at(i);
       }*/
  
  if(S=="ABC") {
	   cout << "ARC" << endl;
	   }else{
	   cout << "ABC" << endl;
	   }
}