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:
Teacher

Context:
In Germany, teachers are mainly civil servants recruited in special university classes, called Lehramtstudien (Teaching Education Studies). There are many differences between the teachers for elementary schools (Grundschule), lower secondary schools (Hauptschule), middle level secondary schools (Realschule) and higher level secondary schools (Gymnasium). Salaries for teachers depend on the civil servants' salary index scale (Bundesbesoldungsordnung).

Question:
What are upper-level secondary schools called?

Gymnasium