diff --git a/lectures b/lectures
index 2a99527..acffa8c 160000
--- a/lectures
+++ b/lectures
@@ -1 +1 @@
-Subproject commit 2a995277f534028a0d558969eb9fd1e74b117395
+Subproject commit acffa8cef796e484afef5cf72c9afd4ecc4f1c54