import java.util.*;
class Main
{
  public static void main(String args[])
  {
    Scanner obj=new Scanner(System.in);
    String s=obj.next();
    if(s.equalsIgnoreCase("ABC"))
       System.out.println("ARC");
    else
       System.out.println("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