diff --git a/09-find_duplicates/task.md b/09-find_duplicates/task.md
index 154ac2e0edbe0e5b472a226d177a9af4a8d43588..280855defc8398e7d572211429dab804e3253fc7 100644
--- a/09-find_duplicates/task.md
+++ b/09-find_duplicates/task.md
@@ -20,3 +20,6 @@ uniquely determined by some its substring or similar properties of the input
 will not be accepted.
 
 As usual, you should submit only the `find_duplicates.{h,py}` file.
+
+Note that due to the space constraints of the Python solutions, tests `10M` and `16M` are
+not used and are always considered successful by ReCodEx.