diff --git a/rag_from_scratch_1_to_4.ipynb b/rag_from_scratch_1_to_4.ipynb
index de094b3..0418d09 100644
--- a/rag_from_scratch_1_to_4.ipynb
+++ b/rag_from_scratch_1_to_4.ipynb
@@ -39,9 +39,11 @@
    "metadata": {},
    "outputs": [],
    "source": [
+    "import os\n",
     "os.environ['LANGCHAIN_TRACING_V2'] = 'true'\n",
     "os.environ['LANGCHAIN_ENDPOINT'] = 'https://api.smith.langchain.com'\n",
-    "os.environ['LANGCHAIN_API_KEY'] = <your-api-key>"
+    "os.environ['LANGCHAIN_API_KEY'] = <your-api-key>\n",
+    "os.environ['OPENAI_API_KEY'] = <openai-api-key>"
    ]
   },
   {