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:
Buddhism

Context:
The three marks of existence may reflect Upanishadic or other influences. K.R. Norman supposes that the these terms were already in use at the Buddha's time, and were familiair to his hearers.

Question:
How many marks of existence reflect Upanishadic influences?

three