Code style improvement

Haskell/p003.hs

@@ -1,14 +1,14 @@
 -- The prime factors of 13195 are 5, 7, 13 and 29.  --
 -- What is the largest prime factor of the number 600851475143?
-import ProjectEuler
 
-maxPrimeFactor :: (Integral n) => n -> n
+import ProjectEuler (isPrime)
+
+maxPrimeFactor :: Integer -> Integer
 maxPrimeFactor n
     | isPrime n         = n         
-    | n `mod` 2 == 0    = maxPrimeFactor $ fromIntegral n `div` 2
-    | otherwise         = maxPrimeFactor $ fromIntegral n `div` head [i | i <- [3,5..], n `mod` i == 0 && isPrime i]
+    | n `mod` 2 == 0    = maxPrimeFactor $ n `div` 2
+    | otherwise         = maxPrimeFactor $ n `div` head [i | i <- [3,5..], n `mod` i == 0 && isPrime i]
 
-main :: IO ()
 main = do
     let result = maxPrimeFactor 600851475143
     putStrLn $ "Project Euler, Problem 3\n"