Read this and answer the question. If the question is unanswerable, say "unanswerable".

A patent is a form of right granted by the government to an inventor, giving the owner the right to exclude others from making, using, selling, offering to sell, and importing an invention for a limited period of time, in exchange for the public disclosure of the invention. An invention is a solution to a specific technological problem, which may be a product or a process and generally has to fulfil three main requirements: it has to be new, not obvious and there needs to be an industrial applicability.:17

How many requirements does an invention need to fulfill for a patent?
three