main :: IO ()
main = do
  putStr  (showGrid board)
  putStr "\n"
  putStr  (showGrid $ head $ solve board)
main :: IO ()
main = do
  putStr  (showGrid board)
  putStr "\n"
  putStr  (showGrid $ head $ solve board)
main = do
  putStr  (showGrid board)
  putStr "\n"
  putStr  (showGrid $ head $ solve board)