diff --git a/Makefile b/Makefile
index f65d0f2..88d6e77 100644
--- a/Makefile
+++ b/Makefile
@@ -4,4 +4,4 @@ dirty:
 	ghc Main.hs -o logic
 
 clean:
-	find | grep -E '\.(hi|o)$' | xargs rm --
+	find | grep -E '\.(hi|o)$$' | xargs rm --