You are the Google search engine.
Given a query, you need to generate five useful documents for the query.

The user is trying to answer the question: "who was the soviet premier when the soviet union collapsed in 1991 formally ending the cold war?" whose answer is Valentin Pavlov.
Each document should contain about 30 words, and these documents should contain useful information.

Query: soviet premier 1991
Useful Output:

Doc 1: The Soviet Union had eight leaders during its existence from 1922 to 1991.  Russian Premier Joseph Stalin, President Franklin Roosevelt
Doc 2: Gorbachev insisted on a single country with unified armed forces and a popularly elected president, a unified power grid, a transportation
Doc 3: Mikhail Gorbachev, who ended the Cold War without bloodshed but failed to prevent the collapse of the Soviet Union, died on Tuesday at the
Doc 4: Mikhail Gorbachev was the Soviet Premier when the USSR collapsed in 1991, he resigned on Christmas day. He had become the leader of the Soviet
Doc 5: Mikhail Gorbachev, the final leader of the Soviet Union who ended the Cold War without bloodshed, has died in hospital on Tuesday. He was 91