import java.util.*;
 
public class Main {
 
    public static void main(String args[]) {
 
        // 入力
        Scanner sc = new Scanner(System.in);
        String s = sc.next();
        sc.close();
 
        // 主処理
        String result;
        switch (s) {
            case "ABC":
                result = "ARC";
                break;
            default:
                result = "ABC";
                break;
        }
 
        // 出力
        System.out.println(result);
    }
}
/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