ans x =
  let i = concat $ take 9 x
      r = drop 9 x
  in
    (ans' i):(ans r)
ans x =
  let i = concat $ take 9 x
      r = drop 9 x
  in
    (ans' i):(ans r)
ans x =
  let i = concat $ take 9 x
      r = drop 9 x
  in
    (ans' i):(ans r)