import java.util.*;

public class Main {

    static int gcd (int a, int b) {return b>0?gcd(b,a%b):a;}
    static int mod = 1000000007;

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

    }

}






 import java.util.*; util.* java public class Main {

    static int gcd (int a, int b) {return b>0?gcd(b,a%b):a;}
    static int mod = 1000000007;

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

    }

} Main static int mod = 1000000007; mod 1000000007 static int gcd (int a, int b) {return b>0?gcd(b,a%b):a;} gcd {return b>0?gcd(b,a%b):a;} return b>0?gcd(b,a%b):a; b>0?gcd(b,a%b):a b>0 b 0 gcd(b,a%b) gcd b a%b a b a int a a int b b public static void main(String[] args)  {
        Scanner sc = new Scanner(System.in);
        String S = sc.next();
        if(S.equals("ARC")){
                System.out.println("ABC");
        } else {
            System.out.println("ARC");
        }

    } main {
        Scanner sc = new Scanner(System.in);
        String S = sc.next();
        if(S.equals("ARC")){
                System.out.println("ABC");
        } else {
            System.out.println("ARC");
        }

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

    static int gcd (int a, int b) {return b>0?gcd(b,a%b):a;}
    static int mod = 1000000007;

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

    }

} public class Main {

    static int gcd (int a, int b) {return b>0?gcd(b,a%b):a;}
    static int mod = 1000000007;

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

    }

} Main
import java.util.*;

public class Main {

    static int gcd (int a, int b) {return b>0?gcd(b,a%b):a;}
    static int mod = 1000000007;

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

    }

}







