It really focuses around spiritual philosophy. And amongst these four Vedas, there are 108 Upanishads. And 108 is considered a very auspicious number in Hinduism. Now you also have Brahmanas, which are commentary. Now to be clear, there are verses in the Vedas that can be many of these, that can be Aryanakas and Upanishads. So these things are not mutually exclusive. Now in the Hindu tradition, one of the unifying factors are the Vedas and the subclassifications or subcategorizations of the Vedas.