diff --git a/Haskell/p023.hs b/Haskell/p023.hs
index 44bb637..67e64e9 100644
--- a/Haskell/p023.hs
+++ b/Haskell/p023.hs
@@ -10,6 +10,7 @@
 --
 -- Find the sum of all the positive integers which cannot be written as the sum of two abundant numbers.
 import Data.List
+import qualified Data.Set as Set
 
 import ProjectEuler (sumProperDivisors)
 
@@ -17,7 +18,7 @@ isAbundant :: (Integral a) => a -> Bool
 isAbundant n = sumProperDivisors n > n
 
 abundantSums :: (Integral a) => [a]
-abundantSums = nub [ x + y | x <- abundantList, y <- abundantList, x + y <= 28123, y >= x ]
+abundantSums = Set.toList $ Set.fromList [ x + y | x <- abundantList, y <- abundantList, x + y <= 28123, y >= x ]
     where abundantList = [ x | x <- [12..28123], isAbundant x ]
 
 sumNotAbundant :: (Integral a) => a