import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 *
 * @author bhavy seth
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        A solver = new A();
        solver.solve(1, in, out);
        out.close();
    }

    static class A {
        public void solve(int testNumber, InputReader sc, PrintWriter out) {
            String s = sc.nextLine();
            if (s.equals("ARC"))
                out.println("ABC");
            else out.println("ARC");
        }

    }

    static class InputReader {
        BufferedReader br;

        public InputReader(InputStream inputStream) {
            br = new BufferedReader(new
                    InputStreamReader(inputStream));
        }

        public String nextLine() {
            String str = "";
            try {
                str = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        }

    }
}
 import java.io.OutputStream; OutputStream java.io import java.io.IOException; IOException java.io import java.io.InputStream; InputStream java.io import java.io.PrintWriter; PrintWriter java.io import java.io.IOException; IOException java.io import java.io.BufferedReader; BufferedReader java.io import java.io.InputStreamReader; InputStreamReader java.io import java.io.InputStream; InputStream java.io public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        A solver = new A();
        solver.solve(1, in, out);
        out.close();
    }

    static class A {
        public void solve(int testNumber, InputReader sc, PrintWriter out) {
            String s = sc.nextLine();
            if (s.equals("ARC"))
                out.println("ABC");
            else out.println("ARC");
        }

    }

    static class InputReader {
        BufferedReader br;

        public InputReader(InputStream inputStream) {
            br = new BufferedReader(new
                    InputStreamReader(inputStream));
        }

        public String nextLine() {
            String str = "";
            try {
                str = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        }

    }
} Main public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        A solver = new A();
        solver.solve(1, in, out);
        out.close();
    } main {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        A solver = new A();
        solver.solve(1, in, out);
        out.close();
    } InputStream inputStream = System.in; inputStream System.in System System.in OutputStream outputStream = System.out; outputStream System.out System System.out InputReader in = new InputReader(inputStream); in new InputReader(inputStream) PrintWriter out = new PrintWriter(outputStream); out new PrintWriter(outputStream) A solver = new A(); solver new A() solver.solve(1, in, out) solver.solve solver 1 in out out.close() out.close out String[] args args static class A {
        public void solve(int testNumber, InputReader sc, PrintWriter out) {
            String s = sc.nextLine();
            if (s.equals("ARC"))
                out.println("ABC");
            else out.println("ARC");
        }

    } A public void solve(int testNumber, InputReader sc, PrintWriter out) {
            String s = sc.nextLine();
            if (s.equals("ARC"))
                out.println("ABC");
            else out.println("ARC");
        } solve {
            String s = sc.nextLine();
            if (s.equals("ARC"))
                out.println("ABC");
            else out.println("ARC");
        } String s = sc.nextLine(); s sc.nextLine() sc.nextLine sc if (s.equals("ARC"))
                out.println("ABC");
            else out.println("ARC"); s.equals("ARC") s.equals s "ARC" out.println("ABC") out.println out "ABC" out.println("ARC") out.println out "ARC" int testNumber testNumber InputReader sc sc PrintWriter out out static class InputReader {
        BufferedReader br;

        public InputReader(InputStream inputStream) {
            br = new BufferedReader(new
                    InputStreamReader(inputStream));
        }

        public String nextLine() {
            String str = "";
            try {
                str = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        }

    } InputReader BufferedReader br; br public InputReader(InputStream inputStream) {
            br = new BufferedReader(new
                    InputStreamReader(inputStream));
        } InputReader {
            br = new BufferedReader(new
                    InputStreamReader(inputStream));
        } br = new BufferedReader(new
                    InputStreamReader(inputStream)) br new BufferedReader(new
                    InputStreamReader(inputStream)) InputStream inputStream inputStream public String nextLine() {
            String str = "";
            try {
                str = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        } nextLine {
            String str = "";
            try {
                str = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        } String str = ""; str "" try {
                str = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            } IOException 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) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        A solver = new A();
        solver.solve(1, in, out);
        out.close();
    }

    static class A {
        public void solve(int testNumber, InputReader sc, PrintWriter out) {
            String s = sc.nextLine();
            if (s.equals("ARC"))
                out.println("ABC");
            else out.println("ARC");
        }

    }

    static class InputReader {
        BufferedReader br;

        public InputReader(InputStream inputStream) {
            br = new BufferedReader(new
                    InputStreamReader(inputStream));
        }

        public String nextLine() {
            String str = "";
            try {
                str = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        }

    }
} public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        A solver = new A();
        solver.solve(1, in, out);
        out.close();
    }

    static class A {
        public void solve(int testNumber, InputReader sc, PrintWriter out) {
            String s = sc.nextLine();
            if (s.equals("ARC"))
                out.println("ABC");
            else out.println("ARC");
        }

    }

    static class InputReader {
        BufferedReader br;

        public InputReader(InputStream inputStream) {
            br = new BufferedReader(new
                    InputStreamReader(inputStream));
        }

        public String nextLine() {
            String str = "";
            try {
                str = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        }

    }
} Main
import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 *
 * @author bhavy seth
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        A solver = new A();
        solver.solve(1, in, out);
        out.close();
    }

    static class A {
        public void solve(int testNumber, InputReader sc, PrintWriter out) {
            String s = sc.nextLine();
            if (s.equals("ARC"))
                out.println("ABC");
            else out.println("ARC");
        }

    }

    static class InputReader {
        BufferedReader br;

        public InputReader(InputStream inputStream) {
            br = new BufferedReader(new
                    InputStreamReader(inputStream));
        }

        public String nextLine() {
            String str = "";
            try {
                str = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        }

    }
}

