You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Plymouth

Context:
Plymouth also has 71 state primary phase schools, 13 state secondary schools, eight special schools and three selective state grammar schools, Devonport High School for Girls, Devonport High School for Boys and Plymouth High School for Girls. There is also an independent school Plymouth College.

Question:
How many state grammar schools are based in Plymouth?

three