
import java.io.DataInputStream;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.PriorityQueue;
import java.util.*;

public class Main {
	public static class pair implements Comparable<pair> {
		int id;
		int ans;

		pair(int x, int y) {

			id = x;
			ans = y;

		}

		public pair() {

		}

		public int compareTo(pair o) {
			// TODO Auto-generated method stub

			return this.id - o.id;
		}
	}

//	static int mod = (int) 998244353.;
	static ArrayList<Integer> gr[];
	static long ar[];
	static Scanner sc = new Scanner(System.in);
	static int pri[] = new int[(int) 1e6 + 5];
	static StringBuilder out = new StringBuilder();

	//static long dp[];

	public static void main(String[] args) throws IOException {
		int t =1;// sc.nextInt();
		
		while (t-- > 0) {

			String s1="ABC";
			String s2="ARC";
			String s=sc.next();
			if(s.equals(s1)) {
				System.out.println(s2);
			}
			else System.out.println(s1);
		}

	}
}
/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