diff --git a/src/CLI.hs b/src/CLI.hs
index 5617a73..5a5cc30 100644
--- a/src/CLI.hs
+++ b/src/CLI.hs
@@ -7,6 +7,7 @@ import Options.Applicative (
     Parser, execParser, flag, flag', fullDesc, header, help, helper, info, long
   )
 import Control.Applicative ((<**>), (<|>))
+import Data.Monoid ((<>))
 import Data.Version (showVersion)
 import qualified Paths_pilu as Pilu (version)