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)

import Control.Monad.ST
import Data.Char
 
 
readInt :: IO Int
readInt = read <$> getLine :: IO Int
 
readIntSplit :: IO [Int]
readIntSplit = map read . words <$> getLine :: IO [Int]
 
readStr :: IO String
readStr = getLine
 
readStrSplit :: IO [String]
readStrSplit = map read . words <$> getLine

solve :: String -> String
solve "ABC" = "ARC"
solve "ARC" = "ABC"

main = do
  s <- readStr
  putStrLn $ solve s