main :: IO ()
  main = do
    let tour = [1 .. 6]
        tours = permutations tour
    display' $ last (sndSort $ mapTour tours)
main :: IO ()
main = do
    let tour = [1 .. 6]
        tours = permutations tour
    display' $ last (sndSort $ mapTour tours)
main = do
    let tour = [1 .. 6]
        tours = permutations tour
    display' $ last (sndSort $ mapTour tours)