/*package whatever //do not write package name here */
import java.util.*;
import java.io.*;

class Main {
	public static void main (String[] args) {
// 		System.out.println("GfG!");
		Scanner input=new Scanner(System.in);
		String S=input.nextLine();
		if(S.equals("ABC"))
		    System.out.println("ARC");
		else
		    System.out.println("ABC");
		input.close();
		
	}
}
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz