diff --git a/src/Main.hs b/src/Main.hs
index da89c38..a946e5e 100644
--- a/src/Main.hs
+++ b/src/Main.hs
@@ -4,6 +4,7 @@ module Main where
 
 import Control.Monad             (when, forever)
 import Data.Text                 (unpack)
+import Data.Monoid
 import Options.Applicative
 import Alea.Diceware
 import Paths_alea                (getDataFileName)