diff --git a/appendix-A/02_installing-python-libraries/requirements.txt b/appendix-A/02_installing-python-libraries/requirements.txt
index 22148e7..41f6fa6 100644
--- a/appendix-A/02_installing-python-libraries/requirements.txt
+++ b/appendix-A/02_installing-python-libraries/requirements.txt
@@ -5,4 +5,5 @@ matplotlib >= 3.7.1
 jupyterlab >= 4.0
 ipywidgets >= 8.0.6
 watermark >= 2.4.2
-torch >= 2.0.1
\ No newline at end of file
+torch >= 2.0.1
+tiktoken >= 0.5.1