Project Euler, Problem #4, Haskell

-- A palindromic number reads the same both ways. The largest
-- palindrome made from the product of two 2-digit numbers is
-- 9009 = 91 × 99. Find the largest palindrome made from the product
-- of two 3-digit numbers.

main :: IO ()
main =
  print $
  maximum
    [ z
    | x <- [100 .. 999]
    , y <- [100 .. 999]
    , let z = x * y
    , show z == reverse (show z)
    ]

-- 906609

-- real 0m0,629s
-- user 0m0,628s
-- sys  0m0,000s