Problem:
Score : 100 points

Problem Statement

An uppercase or lowercase English letter \alpha will be given as input.
If \alpha is uppercase, print A; if it is lowercase, print a.

Constraints

\alpha is an uppercase (A - Z) or lowercase (a - z) English letter.

Input

Input is given from Standard Input in the following format:

α

Output

If \alpha is uppercase, print A; if it is lowercase, print a.

Sample Input 1

B

Sample Output 1

A

B is uppercase, so we should print A.

Sample Input 2

a

Sample Output 2

a

a is lowercase, so we should print a.

Solution in Haskell (GHC 8.8.3) (judge verdict: Wrong Answer)

import Data.Char (isUpper, isLower)
import Data.ByteString.Char8 (ByteString)
import qualified Data.ByteString.Char8 as BSC8

readString :: ByteString -> [String]
readString = map BSC8.unpack . BSC8.words

getString :: IO [String]
getString = readString <$> BSC8.getLine

main :: IO ()
main = do
  [s] <- getString
  case s of
    isUpper -> putStrLn "A"
    isLower -> putStrLn "a"