import java.util.*;
public class Main{
  public static void main(String[] args) {

    Scanner ob = new Scanner(System.in);
    String S = ob.next();
    String result = "";

    if(S.equals("ABC")){
      result += "ARC";
    }
    else{
      result += "ABC";
    }
    System.out.println(result);
  }
}

/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