import java.io.*;

public class Main {
    public static void main(String[] args) {
        String S;

        try (InputScanner is = new InputScanner(System.in)) {
            S = is.next();
        }


        if (S.equals("ARC")) {
            System.out.println("ABC");
        } else {
            System.out.println("ARC");
        }

    }

    //-------------------------------------------------------------------
    public static class InputScanner implements Closeable {
        private final BufferedReader br;
        private String[] element;
        private int elementIndex;

        public InputScanner(InputStream is) {
            this.br = new BufferedReader(new InputStreamReader(is));
        }

        public String next() {
            return this.nextElement();
        }

        //next int
        public int ni() {
            return Integer.parseInt(this.nextElement());
        }

        //next long
        public long li() {
            return Long.parseLong(this.nextElement());
        }

        //next int array
        public int[] nia(int n) {
            int[] arr = new int[n];
            for (int i = 0; i < n; i++) {
                arr[i] = this.ni();
            }
            return arr;
        }

        private void readLine() {
            try {
                this.element = this.br.readLine().split("\\s");
            } catch (IOException e) {
                e.printStackTrace();
            }
            this.elementIndex = 0;
        }

        private String nextElement() {
            if (!hasElement()) {
                this.readLine();
            }
            return this.element[this.elementIndex++];
        }

        private boolean hasElement() {
            return this.element != null && this.element.length > this.elementIndex;
        }

        @Override
        public void close() {
            if (this.br != null) {
                try {
                    this.br.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
//-------------------------------------------------------------------
} import java.io.*; io.* java public class Main {
    public static void main(String[] args) {
        String S;

        try (InputScanner is = new InputScanner(System.in)) {
            S = is.next();
        }


        if (S.equals("ARC")) {
            System.out.println("ABC");
        } else {
            System.out.println("ARC");
        }

    }

    //-------------------------------------------------------------------
    public static class InputScanner implements Closeable {
        private final BufferedReader br;
        private String[] element;
        private int elementIndex;

        public InputScanner(InputStream is) {
            this.br = new BufferedReader(new InputStreamReader(is));
        }

        public String next() {
            return this.nextElement();
        }

        //next int
        public int ni() {
            return Integer.parseInt(this.nextElement());
        }

        //next long
        public long li() {
            return Long.parseLong(this.nextElement());
        }

        //next int array
        public int[] nia(int n) {
            int[] arr = new int[n];
            for (int i = 0; i < n; i++) {
                arr[i] = this.ni();
            }
            return arr;
        }

        private void readLine() {
            try {
                this.element = this.br.readLine().split("\\s");
            } catch (IOException e) {
                e.printStackTrace();
            }
            this.elementIndex = 0;
        }

        private String nextElement() {
            if (!hasElement()) {
                this.readLine();
            }
            return this.element[this.elementIndex++];
        }

        private boolean hasElement() {
            return this.element != null && this.element.length > this.elementIndex;
        }

        @Override
        public void close() {
            if (this.br != null) {
                try {
                    this.br.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
//-------------------------------------------------------------------
} Main public static void main(String[] args) {
        String S;

        try (InputScanner is = new InputScanner(System.in)) {
            S = is.next();
        }


        if (S.equals("ARC")) {
            System.out.println("ABC");
        } else {
            System.out.println("ARC");
        }

    } main {
        String S;

        try (InputScanner is = new InputScanner(System.in)) {
            S = is.next();
        }


        if (S.equals("ARC")) {
            System.out.println("ABC");
        } else {
            System.out.println("ARC");
        }

    } String S; S try (InputScanner is = new InputScanner(System.in)) {
            S = is.next();
        } {
            S = is.next();
        } InputScanner is = new InputScanner(System.in) InputScanner is = new InputScanner(System.in) new InputScanner(System.in) S = is.next() S is.next() is.next is if (S.equals("ARC")) {
            System.out.println("ABC");
        } else {
            System.out.println("ARC");
        } S.equals("ARC") S.equals S "ARC" {
            System.out.println("ABC");
        } System.out.println("ABC") System.out.println System.out System System.out "ABC" {
            System.out.println("ARC");
        } System.out.println("ARC") System.out.println System.out System System.out "ARC" String[] args args public static class InputScanner implements Closeable {
        private final BufferedReader br;
        private String[] element;
        private int elementIndex;

        public InputScanner(InputStream is) {
            this.br = new BufferedReader(new InputStreamReader(is));
        }

        public String next() {
            return this.nextElement();
        }

        //next int
        public int ni() {
            return Integer.parseInt(this.nextElement());
        }

        //next long
        public long li() {
            return Long.parseLong(this.nextElement());
        }

        //next int array
        public int[] nia(int n) {
            int[] arr = new int[n];
            for (int i = 0; i < n; i++) {
                arr[i] = this.ni();
            }
            return arr;
        }

        private void readLine() {
            try {
                this.element = this.br.readLine().split("\\s");
            } catch (IOException e) {
                e.printStackTrace();
            }
            this.elementIndex = 0;
        }

        private String nextElement() {
            if (!hasElement()) {
                this.readLine();
            }
            return this.element[this.elementIndex++];
        }

        private boolean hasElement() {
            return this.element != null && this.element.length > this.elementIndex;
        }

        @Override
        public void close() {
            if (this.br != null) {
                try {
                    this.br.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    } InputScanner private final BufferedReader br; br private String[] element; element private int elementIndex; elementIndex public InputScanner(InputStream is) {
            this.br = new BufferedReader(new InputStreamReader(is));
        } InputScanner {
            this.br = new BufferedReader(new InputStreamReader(is));
        } this.br = new BufferedReader(new InputStreamReader(is)) this.br this this.br new BufferedReader(new InputStreamReader(is)) InputStream is is public String next() {
            return this.nextElement();
        } next {
            return this.nextElement();
        } return this.nextElement(); this.nextElement() this.nextElement this //next int
        public int ni() {
            return Integer.parseInt(this.nextElement());
        } ni {
            return Integer.parseInt(this.nextElement());
        } return Integer.parseInt(this.nextElement()); Integer.parseInt(this.nextElement()) Integer.parseInt Integer this.nextElement() this.nextElement this //next long
        public long li() {
            return Long.parseLong(this.nextElement());
        } li {
            return Long.parseLong(this.nextElement());
        } return Long.parseLong(this.nextElement()); Long.parseLong(this.nextElement()) Long.parseLong Long this.nextElement() this.nextElement this //next int array
        public int[] nia(int n) {
            int[] arr = new int[n];
            for (int i = 0; i < n; i++) {
                arr[i] = this.ni();
            }
            return arr;
        } nia {
            int[] arr = new int[n];
            for (int i = 0; i < n; i++) {
                arr[i] = this.ni();
            }
            return arr;
        } int[] arr = new int[n]; arr new int[n] n for (int i = 0; i < n; i++) {
                arr[i] = this.ni();
            } int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
                arr[i] = this.ni();
            } {
                arr[i] = this.ni();
            } arr[i] = this.ni() arr[i] arr i this.ni() this.ni this return arr; arr int n n private void readLine() {
            try {
                this.element = this.br.readLine().split("\\s");
            } catch (IOException e) {
                e.printStackTrace();
            }
            this.elementIndex = 0;
        } readLine {
            try {
                this.element = this.br.readLine().split("\\s");
            } catch (IOException e) {
                e.printStackTrace();
            }
            this.elementIndex = 0;
        } try {
                this.element = this.br.readLine().split("\\s");
            } catch (IOException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            } IOException e {
                e.printStackTrace();
            } e.printStackTrace() e.printStackTrace e {
                this.element = this.br.readLine().split("\\s");
            } this.element = this.br.readLine().split("\\s") this.element this this.element this.br.readLine().split("\\s") this.br.readLine().split this.br.readLine() this.br.readLine this.br this this.br "\\s" this.elementIndex = 0 this.elementIndex this this.elementIndex 0 private String nextElement() {
            if (!hasElement()) {
                this.readLine();
            }
            return this.element[this.elementIndex++];
        } nextElement {
            if (!hasElement()) {
                this.readLine();
            }
            return this.element[this.elementIndex++];
        } if (!hasElement()) {
                this.readLine();
            } !hasElement() hasElement() hasElement {
                this.readLine();
            } this.readLine() this.readLine this return this.element[this.elementIndex++]; this.element[this.elementIndex++] this.element this this.element this.elementIndex++ this.elementIndex this this.elementIndex private boolean hasElement() {
            return this.element != null && this.element.length > this.elementIndex;
        } hasElement {
            return this.element != null && this.element.length > this.elementIndex;
        } return this.element != null && this.element.length > this.elementIndex; this.element != null && this.element.length > this.elementIndex this.element != null this.element this this.element null this.element.length > this.elementIndex this.element.length this.element this this.element this.element.length this.elementIndex this this.elementIndex @Override
        public void close() {
            if (this.br != null) {
                try {
                    this.br.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        } close {
            if (this.br != null) {
                try {
                    this.br.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        } if (this.br != null) {
                try {
                    this.br.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            } this.br != null this.br this this.br null {
                try {
                    this.br.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            } try {
                    this.br.close();
                } catch (IOException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                } IOException e {
                    e.printStackTrace();
                } e.printStackTrace() e.printStackTrace e {
                    this.br.close();
                } this.br.close() this.br.close this.br this this.br Closeable public class Main {
    public static void main(String[] args) {
        String S;

        try (InputScanner is = new InputScanner(System.in)) {
            S = is.next();
        }


        if (S.equals("ARC")) {
            System.out.println("ABC");
        } else {
            System.out.println("ARC");
        }

    }

    //-------------------------------------------------------------------
    public static class InputScanner implements Closeable {
        private final BufferedReader br;
        private String[] element;
        private int elementIndex;

        public InputScanner(InputStream is) {
            this.br = new BufferedReader(new InputStreamReader(is));
        }

        public String next() {
            return this.nextElement();
        }

        //next int
        public int ni() {
            return Integer.parseInt(this.nextElement());
        }

        //next long
        public long li() {
            return Long.parseLong(this.nextElement());
        }

        //next int array
        public int[] nia(int n) {
            int[] arr = new int[n];
            for (int i = 0; i < n; i++) {
                arr[i] = this.ni();
            }
            return arr;
        }

        private void readLine() {
            try {
                this.element = this.br.readLine().split("\\s");
            } catch (IOException e) {
                e.printStackTrace();
            }
            this.elementIndex = 0;
        }

        private String nextElement() {
            if (!hasElement()) {
                this.readLine();
            }
            return this.element[this.elementIndex++];
        }

        private boolean hasElement() {
            return this.element != null && this.element.length > this.elementIndex;
        }

        @Override
        public void close() {
            if (this.br != null) {
                try {
                    this.br.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
//-------------------------------------------------------------------
} public class Main {
    public static void main(String[] args) {
        String S;

        try (InputScanner is = new InputScanner(System.in)) {
            S = is.next();
        }


        if (S.equals("ARC")) {
            System.out.println("ABC");
        } else {
            System.out.println("ARC");
        }

    }

    //-------------------------------------------------------------------
    public static class InputScanner implements Closeable {
        private final BufferedReader br;
        private String[] element;
        private int elementIndex;

        public InputScanner(InputStream is) {
            this.br = new BufferedReader(new InputStreamReader(is));
        }

        public String next() {
            return this.nextElement();
        }

        //next int
        public int ni() {
            return Integer.parseInt(this.nextElement());
        }

        //next long
        public long li() {
            return Long.parseLong(this.nextElement());
        }

        //next int array
        public int[] nia(int n) {
            int[] arr = new int[n];
            for (int i = 0; i < n; i++) {
                arr[i] = this.ni();
            }
            return arr;
        }

        private void readLine() {
            try {
                this.element = this.br.readLine().split("\\s");
            } catch (IOException e) {
                e.printStackTrace();
            }
            this.elementIndex = 0;
        }

        private String nextElement() {
            if (!hasElement()) {
                this.readLine();
            }
            return this.element[this.elementIndex++];
        }

        private boolean hasElement() {
            return this.element != null && this.element.length > this.elementIndex;
        }

        @Override
        public void close() {
            if (this.br != null) {
                try {
                    this.br.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
//-------------------------------------------------------------------
} Main
import java.io.*;

public class Main {
    public static void main(String[] args) {
        String S;

        try (InputScanner is = new InputScanner(System.in)) {
            S = is.next();
        }


        if (S.equals("ARC")) {
            System.out.println("ABC");
        } else {
            System.out.println("ARC");
        }

    }

    //-------------------------------------------------------------------
    public static class InputScanner implements Closeable {
        private final BufferedReader br;
        private String[] element;
        private int elementIndex;

        public InputScanner(InputStream is) {
            this.br = new BufferedReader(new InputStreamReader(is));
        }

        public String next() {
            return this.nextElement();
        }

        //next int
        public int ni() {
            return Integer.parseInt(this.nextElement());
        }

        //next long
        public long li() {
            return Long.parseLong(this.nextElement());
        }

        //next int array
        public int[] nia(int n) {
            int[] arr = new int[n];
            for (int i = 0; i < n; i++) {
                arr[i] = this.ni();
            }
            return arr;
        }

        private void readLine() {
            try {
                this.element = this.br.readLine().split("\\s");
            } catch (IOException e) {
                e.printStackTrace();
            }
            this.elementIndex = 0;
        }

        private String nextElement() {
            if (!hasElement()) {
                this.readLine();
            }
            return this.element[this.elementIndex++];
        }

        private boolean hasElement() {
            return this.element != null && this.element.length > this.elementIndex;
        }

        @Override
        public void close() {
            if (this.br != null) {
                try {
                    this.br.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
//-------------------------------------------------------------------
}
