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 C# (.NET Core 3.1.201) (judge verdict: Accepted)

using System;

namespace AtCoder
{
    class Program
    {
        static void Main ( string[] args )
        {
            var s = Console.ReadLine ( );
            if (s =="ABC")
            {
                Console.WriteLine ( "ARC" );
            }
            else if (s=="ARC")
            {
                Console.WriteLine ( "ABC" );
            }

        }
    }
}