diff --git a/src/MdToHTML.hs b/src/MdToHTML.hs
index f7f5c18..8d9e865 100644
--- a/src/MdToHTML.hs
+++ b/src/MdToHTML.hs
@@ -7,6 +7,7 @@ module MdToHTML where
 import Control.Applicative
 import Control.Monad
 import Data.List
+import Data.Ord (comparing)
 import Debug.Trace
 import Text.ParserCombinators.ReadP
 import Text.Printf