Given the input sentence, please extract the subject and object containing a certain relation in the sentence according to the following relation types, in the format of "relation1: word1, word2; relation2: word3, word4". Relations include: 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.

“Fed Chair Janet Yellen used a speaking opportunity at the University of Massachusetts to give out far more accurate guidance than all of the Federal Open Market Committee members and Fed officials have put together over the last week.…[A]fter all of that, one speech at a university answers the question the market wanted to know all this time.

Answer: member_of: Janet Yellen, Federal Open Market Committee