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: "What is this South Korean-Chinese boy group formed by S.M. Entertainment in 2011 initially with several members and broke up a year later that released the song "Mama" in 2012?" whose answer is Exo.
Each document should contain about 30 words, and these documents should contain useful information.

Query: South Korean-Chinese boy group formed by S.M. Entertainment 2011
Useful Output:

Doc 1: Formed by SM Entertainment in 2011 and debuting in 2012, EXO has earned a large fan base around the world through diversified musical styles and
Doc 2: S.M. started the first generation of Korean idol groups in the 1990s, with its signature boy band H.O.T. holding its inaugural China concert in
Doc 3: For SM, the major breakthrough came in 2011 when they formed the group EXO. The agency wanted to promote EXO both in South Korea and China
Doc 4: EXO is a twelve-member pop group, formed in Seoul, South Korea in early 2012 by S.M Entertainment. The group EXO is divided into two subgroups
Doc 5: A month later, in April 2012, the Korean-Chinese boy group EXO debuted, with SM targeting not only the Korean market but also the Chinese market