I don't have any better guess than the next person regarding the threshold to move up to a higher royalty tier, but my guess is that number is based on the revenue attributed to the PI component. So my guess is that it is lower for Mavyret than V-pak considering the 50% vs 30% ascribed to the PI in the 2 regimens, respectively (i.e. if it is 1Billion in PI sales it is 2B for total Mav sales versus 3.33B for Vpak)