Instructions: In this task, you will be presented with a context from an academic paper and a question separated with a 
. You have to answer the question based on the context.
Input: TF-IDF (Lexical, Non-Neural) is an important unsupervised baseline. NVDM (Lexical, Neural) is a VAE-based approach for document modeling BIBREF10 . 
 Question: Which lexicon-based models did they compare with?
Output:
TF-IDF NVDM