diff --git a/OJ notes/pages/Leetcode Binary-Tree-Preorder-Traversal.md b/OJ notes/pages/Leetcode Binary-Tree-Preorder-Traversal.md
index fe14b18..685928d 100644
--- a/OJ notes/pages/Leetcode Binary-Tree-Preorder-Traversal.md	
+++ b/OJ notes/pages/Leetcode Binary-Tree-Preorder-Traversal.md	
@@ -20,7 +20,7 @@
 >
 > ##### Revisions:
 >
-> N/A
+> 2022-09-21
 
 ##### Related topics: