import Data.Char

caesar :: Char -> Int -> Char
caesar letter num =
  case c > 122 of
    True  -> chr $ c - 26
    False -> chr c
  where
    a = ord letter
    b = mod num 26
    c = a + b

uncaesar :: Char -> Int -> Char
uncaesar letter num =
  case c < 97 of
    True  -> chr $ c + 26
    False -> chr c
  where
    a = ord letter
    b = mod num 26
    c = a - b