diff --git a/y2020/.gitignore b/y2020/.gitignore
index d2468ef..03c338c 100644
--- a/y2020/.gitignore
+++ b/y2020/.gitignore
@@ -1,3 +1,3 @@
 .stack-work/
-y2020.cabal
-*~
\ No newline at end of file
+*~
+*.cabal
\ No newline at end of file
diff --git a/y2020/package.yaml b/y2020/package.yaml
index cbcf213..4640b30 100644
--- a/y2020/package.yaml
+++ b/y2020/package.yaml
@@ -21,6 +21,7 @@ description:         Please see the README on GitHub at <https://github.com/mx42
 
 dependencies:
 - base >= 4.7 && < 5
+- sort
 - split
 - containers