import java.util.*;
public class Main {
    public void solve() {
        Scanner scan = new Scanner(System.in);
        String S = scan.next();
        if(S.equals("ARC"))System.out.println("ABC");
        else if(S.equals("ABC"))System.out.println("ARC");
    }

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

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

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

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

    public static void main(String[] args) {
        new Main().solve();
    }
}