import java.util.*;
public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		// 文字列の入力
		String lineString = sc.nextLine();

		// 出力
		System.out.println(lineString.equals("ARC") ? "ABC" : "ARC");
		sc.close();
	}
} import java.util.*; util.* java public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		// 文字列の入力
		String lineString = sc.nextLine();

		// 出力
		System.out.println(lineString.equals("ARC") ? "ABC" : "ARC");
		sc.close();
	}
} Main public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		// 文字列の入力
		String lineString = sc.nextLine();

		// 出力
		System.out.println(lineString.equals("ARC") ? "ABC" : "ARC");
		sc.close();
	} main {
		Scanner sc = new Scanner(System.in);
		// 文字列の入力
		String lineString = sc.nextLine();

		// 出力
		System.out.println(lineString.equals("ARC") ? "ABC" : "ARC");
		sc.close();
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) String lineString = sc.nextLine(); lineString sc.nextLine() sc.nextLine sc System.out.println(lineString.equals("ARC") ? "ABC" : "ARC") System.out.println System.out System System.out lineString.equals("ARC") ? "ABC" : "ARC" lineString.equals("ARC") lineString.equals lineString "ARC" "ABC" "ARC" sc.close() sc.close sc String[] args args public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		// 文字列の入力
		String lineString = sc.nextLine();

		// 出力
		System.out.println(lineString.equals("ARC") ? "ABC" : "ARC");
		sc.close();
	}
} public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		// 文字列の入力
		String lineString = sc.nextLine();

		// 出力
		System.out.println(lineString.equals("ARC") ? "ABC" : "ARC");
		sc.close();
	}
} Main
import java.util.*;
public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		// 文字列の入力
		String lineString = sc.nextLine();

		// 出力
		System.out.println(lineString.equals("ARC") ? "ABC" : "ARC");
		sc.close();
	}
}
