import java.math.BigInteger;
import java.util.Scanner;
class  Main{
  public   static  void main(String[]args){
Scanner in =new Scanner(System.in);
String s;
s=in.next();
if (s.equals("ABC"))
  System.out.print("ARC");
else  System.out.print("ABC");





  }
}
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz