Project Euler Problem 074

import Data.List
import Data.Char
facl :: [Integer]
facl = 1:scanl1 (*) [1..9] -- 0! == 1
fac :: Int -> Integer
fac = (facl!!)
cha :: Integer -> [Integer]
cha nn = imp nn [] where
  imp n acc | n`elem` acc = acc
  imp n acc = imp r (n:acc) where r = sum $ map (fac.digitToInt) $ show n
ans :: Int
ans = length $ filter ((==60).length.cha) [1..1000000] --10万で10秒ぐらいなのでコンパイルして試す
--402
main :: IO ()
main = print ans