import System.IO.Unsafe (unsafePerformIO)

sudan n x y = unsafePerformIO $ do
                putStrLn ("sudan " ++ show n ++ " " ++ show x ++ " " ++ show y)
                return (realSudan n x y)

realSudan n x y | n == 0    = x + y
                | y == 0    = x
                | otherwise = sudan (n - 1) sudan' (sudan' + y)
    where sudan' = sudan n x (y - 1)

sudTup (n, x, y) = sudan n x y
sudList [n, x, y] = sudTup (n, x, y)

main = print (sudList [1, 5, 4])