import java.util.Scanner;
import java.util.Arrays;
class Main{
public static void main(String[] args){
Scanner scan = new Scanner(System.in);
 
String S = scan.next();

  if ("ABC".equals(S)){
    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