import Data.Char (isUpper, isLower, toUpper, toLower)

toggleCases :: String -> String
toggleCases = map toggleCases'
    where
        toggleCases' c
            | isUpper c = toLower c
            | isLower c = toUpper c
            | otherwise = c

main :: IO ()
main = putStrLn . toggleCases =<< getLine