Problem:
Score : 100 points

Problem Statement

AtCoder Inc. holds a contest every Saturday.

There are two types of contests called ABC and ARC, and just one of them is held at a time.

The company holds these two types of contests alternately: an ARC follows an ABC and vice versa.

Given a string S representing the type of the contest held last week, print the string representing the type of the contest held this week.

Constraints

S is ABC or ARC.

Input

Input is given from Standard Input in the following format:

S

Output

Print the string representing the type of the contest held this week.

Sample Input 1

ABC

Sample Output 1

ARC

They held an ABC last week, so they will hold an ARC this week.

Solution in Java (OpenJDK 11.0.6) (judge verdict: Accepted)

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();
                }
            }
        }
    }
//-------------------------------------------------------------------
}