eul4 _ = maximum [p | x <- [100..1000], y <- [100..1000], let p = x*y, isPalin p]
eul4 _ = maximum [p | x <- [100..1000], y <- [100..1000], let p = x*y, isPalin p]
eul4 _ = maximum [p | x <- [100..1000], y <- [100..1000], let p = x*y, isPalin p]