import java.util.*;
import java.lang.*;
import java.io.*;

/* Name of the class has to be "Main" only if the class is public. */
class Main
{
	public static void main (String[] args) throws java.lang.Exception
	{
		// your code goes here
		try {
		    Scanner sc=new Scanner(System.in);
		    String s=sc.next();
		    if(s.equals("ARC"))
		    System.out.println("ABC");
		    else
		    System.out.println("ARC");
		} catch(Exception e) {
		}
	}
} import java.util.*; util.* java import java.lang.*; lang.* java import java.io.*; io.* java class Main
{
	public static void main (String[] args) throws java.lang.Exception
	{
		// your code goes here
		try {
		    Scanner sc=new Scanner(System.in);
		    String s=sc.next();
		    if(s.equals("ARC"))
		    System.out.println("ABC");
		    else
		    System.out.println("ARC");
		} catch(Exception e) {
		}
	}
} Main public static void main (String[] args) throws java.lang.Exception
	{
		// your code goes here
		try {
		    Scanner sc=new Scanner(System.in);
		    String s=sc.next();
		    if(s.equals("ARC"))
		    System.out.println("ABC");
		    else
		    System.out.println("ARC");
		} catch(Exception e) {
		}
	} main {
		// your code goes here
		try {
		    Scanner sc=new Scanner(System.in);
		    String s=sc.next();
		    if(s.equals("ARC"))
		    System.out.println("ABC");
		    else
		    System.out.println("ARC");
		} catch(Exception e) {
		}
	} try {
		    Scanner sc=new Scanner(System.in);
		    String s=sc.next();
		    if(s.equals("ARC"))
		    System.out.println("ABC");
		    else
		    System.out.println("ARC");
		} catch(Exception e) {
		} catch(Exception e) {
		} Exception e {
		} {
		    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 System.out System System.out "ABC" System.out.println("ARC") System.out.println System.out System System.out "ARC" String[] args args
import java.util.*;
import java.lang.*;
import java.io.*;

/* Name of the class has to be "Main" only if the class is public. */
class Main
{
	public static void main (String[] args) throws java.lang.Exception
	{
		// your code goes here
		try {
		    Scanner sc=new Scanner(System.in);
		    String s=sc.next();
		    if(s.equals("ARC"))
		    System.out.println("ABC");
		    else
		    System.out.println("ARC");
		} catch(Exception e) {
		}
	}
}
