What is the relationship between Baidu and search engine in the context of the input sentence. Choose an answer from: product/material produced; manufacturer; distributed by; industry; position held; original broadcaster; owned by; founded by; distribution format; headquarters location; stock exchange; currency; parent organization; chief executive officer; director/manager; owner of; operator; member of; employer; chairperson; platform; subsidiary; legal form; publisher; developer; brand; business division; location of formation; creator.

And on the other side, besides Tmall Auto, we have been also cooperating with Baidu Youjia, and that is the auto segment of the Baidu portal, which is the largest search engine in China.

Answer: product_or_material_produced