Hi all! I tried to write a Chatbot for asking questions about an upload PDF. If the PDF is too long (es 70 pages) i get this error: BadRequestError: Error code: 400 - {'error': {'message': "This model's maximum context length is 16385 tokens. However, your messages resulted in 28870 tokens. Please reduce the length of the messages.", 'type': 'invalid_request_error', 'param': 'messages', 'code': 'context_length_exceeded'}} the errore arises after i have create the FAISS DB and when i ask the first question I am using Streamlit and lagnchain. here is my funcition for chunking: ------- def get_pdf_text(pdf): pdf_reader = PdfReader(pdf) text = "" for page in pdf_reader.pages: text += page.extract_text() return text def get_text_chunks(text): text_splitter = CharacterTextSplitter(separator="/n") chunks=text_splitter.split_text(text) return chunks def create_db(text, embedding=OpenAIEmbeddings()): # Convert the document chunks to embedding and save them to the vector store vectordb1 = FAISS.from_texts(text, embedding) return vectordb1 ----------- here is my retrieval chain: def get_conversation_chain(vectorstore): llm = ChatOpenAI() # llm = HuggingFaceHub(repo_id="google/flan-t5-xxl", model_kwargs={"temperature":0.5, "max_length":512}) memory = ConversationBufferMemory( memory_key='chat_history', return_messages=True) conversation_chain = ConversationalRetrievalChain.from_llm( llm=llm, retriever=vectorstore.as_retriever(), memory=memory ) return conversation_chain How can i reduce the number of tokens?