Code style improvement

Haskell/p001.hs

@@ -1,11 +1,11 @@
 -- If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23.
 --
 -- Find the sum of all the multiples of 3 or 5 below 1000.
-sumMultiples :: (Integral n) => n
+
+sumMultiples :: Integer
 sumMultiples = sum(filter p [ n | n <- [1..999] ])
                 where p n = n `mod` 3 == 0 || n `mod` 5 == 0
 
-main :: IO ()
 main =  do
     let result = sumMultiples
     putStrLn $ "Project Euler, Problem 1\n"