import java.util.*;
 
public class Main{
 
  public static void main(String args[])
  {
		
    Scanner s = new Scanner (System.in);
    String input=s.next();
    
    if(input.contains("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