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 were the main countries involved in the korean war?" whose answer is Soviet Union.
Each document should contain about 30 words, and these documents should contain useful information.

Query: main countries involved in the korean war
Useful Output:

Doc 1: The Korean War (1950-1953) was a short but brutal conflict between North Korea, backed by China and the Soviet Union, and South Korea, backed by a United
Doc 2: More than three million of these were communists from North Korea, China and Russia. Opposing them were almost three million from South Korea
Doc 3: India condemned North Korea as an aggressor when the Korean War started, supporting Security Council resolutions 82 and 83 on the crisis.
Doc 4: Great Britain, Canada, France, Belgium, the Netherlands, Colombia, Ethiopia, South Africa, New Zealand, Türkiye, Greece, Thailand, Philippines
Doc 5: Those countries located far away from Korea, such as Ethiopia, the Republic of South Africa, and Colombia in South America, also participated in the Korean War.