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.

Federal Reserve Chairwoman Janet Yellen last week referred to concerns about the "deftness" of China's response to downside risks, while Goldman Sachs Chief Executive Officer Lloyd Blankfein called the handling of its stock market collapse "ham-handed."

Answer: chief_executive_officer: Goldman Sachs, Lloyd Blankfein; position_held: Lloyd Blankfein, Chief Executive Officer; employer: Lloyd Blankfein, Goldman Sachs