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 Haskell (GHC 8.8.3) (judge verdict: Accepted)

{-# LANGUAGE PartialTypeSignatures #-}
{-# LANGUAGE LambdaCase #-}
module Main (main) where

import Control.Monad
import qualified Data.ByteString.Char8 as C8

main :: IO ()
main = readString >>= output . solve

solve :: String -> _
solve = \case
  "ABC" -> "ARC"
  "ARC" -> "ABC"

output :: _ -> IO ()
output = putStrLn

readString :: IO String
readString = C8.unpack <$> C8.getLine