import java.util.Scanner;

public class Main{
  public static void main(String[] args){
    Scanner scan = new Scanner(System.in);
    String S = scan.next();
    String ans = "";
    
    if(S.equals("ABC")){
      ans = "ARC";
    }else if(S.equals("ARC")){
      ans = "ABC";
    }
    
    System.out.println(ans);
  }
} import java.util.Scanner; Scanner java.util public class Main{
  public static void main(String[] args){
    Scanner scan = new Scanner(System.in);
    String S = scan.next();
    String ans = "";
    
    if(S.equals("ABC")){
      ans = "ARC";
    }else if(S.equals("ARC")){
      ans = "ABC";
    }
    
    System.out.println(ans);
  }
} Main public static void main(String[] args){
    Scanner scan = new Scanner(System.in);
    String S = scan.next();
    String ans = "";
    
    if(S.equals("ABC")){
      ans = "ARC";
    }else if(S.equals("ARC")){
      ans = "ABC";
    }
    
    System.out.println(ans);
  } main {
    Scanner scan = new Scanner(System.in);
    String S = scan.next();
    String ans = "";
    
    if(S.equals("ABC")){
      ans = "ARC";
    }else if(S.equals("ARC")){
      ans = "ABC";
    }
    
    System.out.println(ans);
  } Scanner scan = new Scanner(System.in); scan new Scanner(System.in) String S = scan.next(); S scan.next() scan.next scan String ans = ""; ans "" if(S.equals("ABC")){
      ans = "ARC";
    }else if(S.equals("ARC")){
      ans = "ABC";
    } S.equals("ABC") S.equals S "ABC" {
      ans = "ARC";
    } ans = "ARC" ans "ARC" if(S.equals("ARC")){
      ans = "ABC";
    } S.equals("ARC") S.equals S "ARC" {
      ans = "ABC";
    } ans = "ABC" ans "ABC" System.out.println(ans) System.out.println System.out System System.out ans String[] args args public class Main{
  public static void main(String[] args){
    Scanner scan = new Scanner(System.in);
    String S = scan.next();
    String ans = "";
    
    if(S.equals("ABC")){
      ans = "ARC";
    }else if(S.equals("ARC")){
      ans = "ABC";
    }
    
    System.out.println(ans);
  }
} public class Main{
  public static void main(String[] args){
    Scanner scan = new Scanner(System.in);
    String S = scan.next();
    String ans = "";
    
    if(S.equals("ABC")){
      ans = "ARC";
    }else if(S.equals("ARC")){
      ans = "ABC";
    }
    
    System.out.println(ans);
  }
} Main
import java.util.Scanner;

public class Main{
  public static void main(String[] args){
    Scanner scan = new Scanner(System.in);
    String S = scan.next();
    String ans = "";
    
    if(S.equals("ABC")){
      ans = "ARC";
    }else if(S.equals("ARC")){
      ans = "ABC";
    }
    
    System.out.println(ans);
  }
}