diff --git a/lectures/22_hash_tables_I/README.md b/lectures/22_hash_tables_I/README.md
index 8b05df6..dba6e0f 100644
--- a/lectures/22_hash_tables_I/README.md
+++ b/lectures/22_hash_tables_I/README.md
@@ -152,6 +152,7 @@ std::string identify(Node* phonebook[PHONEBOOK_SIZE], int number) {
 
 ## 22.9 What makes a Good Hash Function?
 
+- Deterministic – same input always produces the same hash.
 - Goals: fast O(1) computation and a random, uniform distribution of keys throughout the table,
 despite the actual distribution of keys that are to be stored.
 - For example, using: f(k) = abs(k)%N as our hash function satisfies the first requirement, but may not