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

public class Main {
	public static void main(String[] args) {
		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");
		}
	}
} import java.io.*; io.* java import java.util.*; util.* java public class Main {
	public static void main(String[] args) {
		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");
		}
	}
} Main public static void main(String[] args) {
		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");
		}
	} main {
		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("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("ARC") System.out.println System.out System System.out "ARC" String[] args args public class Main {
	public static void main(String[] args) {
		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 class Main {
	public static void main(String[] args) {
		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");
		}
	}
} Main
import java.io.*;
import java.util.*;

public class Main {
	public static void main(String[] args) {
		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");
		}
	}
}