Read the passage, and then answer the questions.

Have you ever seen the film School of Rock? It’s about a rock musician who became a teacher. The film is based on a real music school which is run by Paul Green. Paul Green started the first School of Rock in 1998 in Philadelphia in the USA. He gave students rock music lessons after school, but he wanted to do more. Now he gives them the chance to play in rock concerts. “Some of our students have never played in front of a real audience before. We teach them how to do it.” he says. He has already taught hundreds of young people to be rock performers, and now there are 30 schools of rock in different towns in the USA.

How many students has he taught?