import java.util.Scanner;

class Main {

    public static void main(String[] args) {
        Scanner stdIn=new Scanner(System.in);

        String S=stdIn.next();
        String B="ABC";
        String R="ARC";

        if(S.equals(B)){
            System.out.println(R);
            
        }
        else if(S.equals(R)){
            System.out.println(B);
            
        }
        
        
    }

} import java.util.Scanner; Scanner java.util class Main {

    public static void main(String[] args) {
        Scanner stdIn=new Scanner(System.in);

        String S=stdIn.next();
        String B="ABC";
        String R="ARC";

        if(S.equals(B)){
            System.out.println(R);
            
        }
        else if(S.equals(R)){
            System.out.println(B);
            
        }
        
        
    }

} Main public static void main(String[] args) {
        Scanner stdIn=new Scanner(System.in);

        String S=stdIn.next();
        String B="ABC";
        String R="ARC";

        if(S.equals(B)){
            System.out.println(R);
            
        }
        else if(S.equals(R)){
            System.out.println(B);
            
        }
        
        
    } main {
        Scanner stdIn=new Scanner(System.in);

        String S=stdIn.next();
        String B="ABC";
        String R="ARC";

        if(S.equals(B)){
            System.out.println(R);
            
        }
        else if(S.equals(R)){
            System.out.println(B);
            
        }
        
        
    } Scanner stdIn=new Scanner(System.in); stdIn new Scanner(System.in) String S=stdIn.next(); S stdIn.next() stdIn.next stdIn String B="ABC"; B "ABC" String R="ARC"; R "ARC" if(S.equals(B)){
            System.out.println(R);
            
        }
        else if(S.equals(R)){
            System.out.println(B);
            
        } S.equals(B) S.equals S B {
            System.out.println(R);
            
        } System.out.println(R) System.out.println System.out System System.out R if(S.equals(R)){
            System.out.println(B);
            
        } S.equals(R) S.equals S R {
            System.out.println(B);
            
        } System.out.println(B) System.out.println System.out System System.out B String[] args args
import java.util.Scanner;

class Main {

    public static void main(String[] args) {
        Scanner stdIn=new Scanner(System.in);

        String S=stdIn.next();
        String B="ABC";
        String R="ARC";

        if(S.equals(B)){
            System.out.println(R);
            
        }
        else if(S.equals(R)){
            System.out.println(B);
            
        }
        
        
    }

}