checkChar :: Char -> Char
checkChar n
  | ('a' <= n && n <= 'z') = 'a'
  | ('A' <= n && n <= 'Z') = 'A'

fac :: Int -> Int
fac n
  | n <= 1 = 1
  | n > 1 = n*(fac (n-1))

main = do
    x <- getChar
    putChar (checkChar x)
    putChar '\n'
