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# (Mono-csc 3.5.0) (judge verdict: Accepted)

using System;
class Program
{
	static void Main(string[] args)
	{
		string s = Console.ReadLine();
		//出力
      if(s == "ABC")
      {
        Console.WriteLine("ARC");
      }
      else
      {
        Console.WriteLine("ABC");
      }
        
		
	}
}