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.

MOSCOW, Sept 4 Rosneft plans to launch the plant to liquefy natural gas (LNG) on Russia's Pacific Island of Sakhalin after 2020, Chief Executive Igor Sechin said in his presentation, behind the initial schedule.

Answer: chief_executive_officer: Rosneft, Igor Sechin; director_/_manager: Rosneft, Igor Sechin