import java.util.Scanner;

public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        StringBuilder sb = new StringBuilder();
        while(sc.hasNextLine())
            sb.append(sc.nextLine());
        if (sb.toString().equals("ARC")) {
            System.out.println("ABC");
            return;
        }
        if (sb.toString().equals("ABC")) {
            System.out.println("ARC");
            return;
        }
    }
} import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        StringBuilder sb = new StringBuilder();
        while(sc.hasNextLine())
            sb.append(sc.nextLine());
        if (sb.toString().equals("ARC")) {
            System.out.println("ABC");
            return;
        }
        if (sb.toString().equals("ABC")) {
            System.out.println("ARC");
            return;
        }
    }
} Main public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        StringBuilder sb = new StringBuilder();
        while(sc.hasNextLine())
            sb.append(sc.nextLine());
        if (sb.toString().equals("ARC")) {
            System.out.println("ABC");
            return;
        }
        if (sb.toString().equals("ABC")) {
            System.out.println("ARC");
            return;
        }
    } main {
        Scanner sc = new Scanner(System.in);
        StringBuilder sb = new StringBuilder();
        while(sc.hasNextLine())
            sb.append(sc.nextLine());
        if (sb.toString().equals("ARC")) {
            System.out.println("ABC");
            return;
        }
        if (sb.toString().equals("ABC")) {
            System.out.println("ARC");
            return;
        }
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) StringBuilder sb = new StringBuilder(); sb new StringBuilder() while(sc.hasNextLine())
            sb.append(sc.nextLine()); sc.hasNextLine() sc.hasNextLine sc sb.append(sc.nextLine()) sb.append sb sc.nextLine() sc.nextLine sc if (sb.toString().equals("ARC")) {
            System.out.println("ABC");
            return;
        } sb.toString().equals("ARC") sb.toString().equals sb.toString() sb.toString sb "ARC" {
            System.out.println("ABC");
            return;
        } System.out.println("ABC") System.out.println System.out System System.out "ABC" return; if (sb.toString().equals("ABC")) {
            System.out.println("ARC");
            return;
        } sb.toString().equals("ABC") sb.toString().equals sb.toString() sb.toString sb "ABC" {
            System.out.println("ARC");
            return;
        } System.out.println("ARC") System.out.println System.out System System.out "ARC" return; String[] args args public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        StringBuilder sb = new StringBuilder();
        while(sc.hasNextLine())
            sb.append(sc.nextLine());
        if (sb.toString().equals("ARC")) {
            System.out.println("ABC");
            return;
        }
        if (sb.toString().equals("ABC")) {
            System.out.println("ARC");
            return;
        }
    }
} public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        StringBuilder sb = new StringBuilder();
        while(sc.hasNextLine())
            sb.append(sc.nextLine());
        if (sb.toString().equals("ARC")) {
            System.out.println("ABC");
            return;
        }
        if (sb.toString().equals("ABC")) {
            System.out.println("ARC");
            return;
        }
    }
} Main
import java.util.Scanner;

public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        StringBuilder sb = new StringBuilder();
        while(sc.hasNextLine())
            sb.append(sc.nextLine());
        if (sb.toString().equals("ARC")) {
            System.out.println("ABC");
            return;
        }
        if (sb.toString().equals("ABC")) {
            System.out.println("ARC");
            return;
        }
    }
}
