import java.io.BufferedWriter;
import java.io.OutputStreamWriter;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.StringTokenizer;
 
public class Main {
    public static void main(String[] args) {
        FastReader reader = new FastReader();
        BufferedWriter log = new BufferedWriter(new OutputStreamWriter(System.out));
        try {
            String s = reader.nextLine();
            if (s.equals("ARC")) {
                log.write("ABC");
            } else {
                log.write("ARC");
            }
            log.flush();
            log.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
  	static class FastReader {
    BufferedReader br;
    StringTokenizer st;
 
    public FastReader() {
        br = new BufferedReader(new InputStreamReader(System.in));
    }
 
    public String next() {
        while (st == null || !st.hasMoreElements()) {
            try {
                st = new StringTokenizer(br.readLine());
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return st.nextToken();
    }
 
    public int nextInt() {
        return Integer.parseInt(next());
    }
 
    public long nextLong() {
        return Long.parseLong(next());
    }
 
    public String nextLine() {
        String str = "";
        try {
            str = br.readLine();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return str;
    }
}
} import java.io.BufferedWriter; BufferedWriter java.io import java.io.OutputStreamWriter; OutputStreamWriter java.io import java.io.BufferedReader; BufferedReader java.io import java.io.InputStreamReader; InputStreamReader java.io import java.util.StringTokenizer; StringTokenizer java.util public class Main {
    public static void main(String[] args) {
        FastReader reader = new FastReader();
        BufferedWriter log = new BufferedWriter(new OutputStreamWriter(System.out));
        try {
            String s = reader.nextLine();
            if (s.equals("ARC")) {
                log.write("ABC");
            } else {
                log.write("ARC");
            }
            log.flush();
            log.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
  	static class FastReader {
    BufferedReader br;
    StringTokenizer st;
 
    public FastReader() {
        br = new BufferedReader(new InputStreamReader(System.in));
    }
 
    public String next() {
        while (st == null || !st.hasMoreElements()) {
            try {
                st = new StringTokenizer(br.readLine());
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return st.nextToken();
    }
 
    public int nextInt() {
        return Integer.parseInt(next());
    }
 
    public long nextLong() {
        return Long.parseLong(next());
    }
 
    public String nextLine() {
        String str = "";
        try {
            str = br.readLine();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return str;
    }
}
} Main public static void main(String[] args) {
        FastReader reader = new FastReader();
        BufferedWriter log = new BufferedWriter(new OutputStreamWriter(System.out));
        try {
            String s = reader.nextLine();
            if (s.equals("ARC")) {
                log.write("ABC");
            } else {
                log.write("ARC");
            }
            log.flush();
            log.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    } main {
        FastReader reader = new FastReader();
        BufferedWriter log = new BufferedWriter(new OutputStreamWriter(System.out));
        try {
            String s = reader.nextLine();
            if (s.equals("ARC")) {
                log.write("ABC");
            } else {
                log.write("ARC");
            }
            log.flush();
            log.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    } FastReader reader = new FastReader(); reader new FastReader() BufferedWriter log = new BufferedWriter(new OutputStreamWriter(System.out)); log new BufferedWriter(new OutputStreamWriter(System.out)) try {
            String s = reader.nextLine();
            if (s.equals("ARC")) {
                log.write("ABC");
            } else {
                log.write("ARC");
            }
            log.flush();
            log.close();
        } catch (Exception e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        } Exception e {
            e.printStackTrace();
        } e.printStackTrace() e.printStackTrace e {
            String s = reader.nextLine();
            if (s.equals("ARC")) {
                log.write("ABC");
            } else {
                log.write("ARC");
            }
            log.flush();
            log.close();
        } String s = reader.nextLine(); s reader.nextLine() reader.nextLine reader if (s.equals("ARC")) {
                log.write("ABC");
            } else {
                log.write("ARC");
            } s.equals("ARC") s.equals s "ARC" {
                log.write("ABC");
            } log.write("ABC") log.write log "ABC" {
                log.write("ARC");
            } log.write("ARC") log.write log "ARC" log.flush() log.flush log log.close() log.close log String[] args args static class FastReader {
    BufferedReader br;
    StringTokenizer st;
 
    public FastReader() {
        br = new BufferedReader(new InputStreamReader(System.in));
    }
 
    public String next() {
        while (st == null || !st.hasMoreElements()) {
            try {
                st = new StringTokenizer(br.readLine());
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return st.nextToken();
    }
 
    public int nextInt() {
        return Integer.parseInt(next());
    }
 
    public long nextLong() {
        return Long.parseLong(next());
    }
 
    public String nextLine() {
        String str = "";
        try {
            str = br.readLine();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return str;
    }
} FastReader BufferedReader br; br StringTokenizer st; st public FastReader() {
        br = new BufferedReader(new InputStreamReader(System.in));
    } FastReader {
        br = new BufferedReader(new InputStreamReader(System.in));
    } br = new BufferedReader(new InputStreamReader(System.in)) br new BufferedReader(new InputStreamReader(System.in)) public String next() {
        while (st == null || !st.hasMoreElements()) {
            try {
                st = new StringTokenizer(br.readLine());
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return st.nextToken();
    } next {
        while (st == null || !st.hasMoreElements()) {
            try {
                st = new StringTokenizer(br.readLine());
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return st.nextToken();
    } while (st == null || !st.hasMoreElements()) {
            try {
                st = new StringTokenizer(br.readLine());
            } catch (Exception e) {
                e.printStackTrace();
            }
        } st == null || !st.hasMoreElements() st == null st null !st.hasMoreElements() st.hasMoreElements() st.hasMoreElements st {
            try {
                st = new StringTokenizer(br.readLine());
            } catch (Exception e) {
                e.printStackTrace();
            }
        } try {
                st = new StringTokenizer(br.readLine());
            } catch (Exception e) {
                e.printStackTrace();
            } catch (Exception e) {
                e.printStackTrace();
            } Exception e {
                e.printStackTrace();
            } e.printStackTrace() e.printStackTrace e {
                st = new StringTokenizer(br.readLine());
            } st = new StringTokenizer(br.readLine()) st new StringTokenizer(br.readLine()) return st.nextToken(); st.nextToken() st.nextToken st public int nextInt() {
        return Integer.parseInt(next());
    } nextInt {
        return Integer.parseInt(next());
    } return Integer.parseInt(next()); Integer.parseInt(next()) Integer.parseInt Integer next() next public long nextLong() {
        return Long.parseLong(next());
    } nextLong {
        return Long.parseLong(next());
    } return Long.parseLong(next()); Long.parseLong(next()) Long.parseLong Long next() next public String nextLine() {
        String str = "";
        try {
            str = br.readLine();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return str;
    } nextLine {
        String str = "";
        try {
            str = br.readLine();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return str;
    } String str = ""; str "" try {
            str = br.readLine();
        } catch (Exception e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        } Exception e {
            e.printStackTrace();
        } e.printStackTrace() e.printStackTrace e {
            str = br.readLine();
        } str = br.readLine() str br.readLine() br.readLine br return str; str public class Main {
    public static void main(String[] args) {
        FastReader reader = new FastReader();
        BufferedWriter log = new BufferedWriter(new OutputStreamWriter(System.out));
        try {
            String s = reader.nextLine();
            if (s.equals("ARC")) {
                log.write("ABC");
            } else {
                log.write("ARC");
            }
            log.flush();
            log.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
  	static class FastReader {
    BufferedReader br;
    StringTokenizer st;
 
    public FastReader() {
        br = new BufferedReader(new InputStreamReader(System.in));
    }
 
    public String next() {
        while (st == null || !st.hasMoreElements()) {
            try {
                st = new StringTokenizer(br.readLine());
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return st.nextToken();
    }
 
    public int nextInt() {
        return Integer.parseInt(next());
    }
 
    public long nextLong() {
        return Long.parseLong(next());
    }
 
    public String nextLine() {
        String str = "";
        try {
            str = br.readLine();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return str;
    }
}
} public class Main {
    public static void main(String[] args) {
        FastReader reader = new FastReader();
        BufferedWriter log = new BufferedWriter(new OutputStreamWriter(System.out));
        try {
            String s = reader.nextLine();
            if (s.equals("ARC")) {
                log.write("ABC");
            } else {
                log.write("ARC");
            }
            log.flush();
            log.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
  	static class FastReader {
    BufferedReader br;
    StringTokenizer st;
 
    public FastReader() {
        br = new BufferedReader(new InputStreamReader(System.in));
    }
 
    public String next() {
        while (st == null || !st.hasMoreElements()) {
            try {
                st = new StringTokenizer(br.readLine());
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return st.nextToken();
    }
 
    public int nextInt() {
        return Integer.parseInt(next());
    }
 
    public long nextLong() {
        return Long.parseLong(next());
    }
 
    public String nextLine() {
        String str = "";
        try {
            str = br.readLine();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return str;
    }
}
} Main
import java.io.BufferedWriter;
import java.io.OutputStreamWriter;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.StringTokenizer;
 
public class Main {
    public static void main(String[] args) {
        FastReader reader = new FastReader();
        BufferedWriter log = new BufferedWriter(new OutputStreamWriter(System.out));
        try {
            String s = reader.nextLine();
            if (s.equals("ARC")) {
                log.write("ABC");
            } else {
                log.write("ARC");
            }
            log.flush();
            log.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
  	static class FastReader {
    BufferedReader br;
    StringTokenizer st;
 
    public FastReader() {
        br = new BufferedReader(new InputStreamReader(System.in));
    }
 
    public String next() {
        while (st == null || !st.hasMoreElements()) {
            try {
                st = new StringTokenizer(br.readLine());
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return st.nextToken();
    }
 
    public int nextInt() {
        return Integer.parseInt(next());
    }
 
    public long nextLong() {
        return Long.parseLong(next());
    }
 
    public String nextLine() {
        String str = "";
        try {
            str = br.readLine();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return str;
    }
}
}