cities is just that places there was another technologic air conditioning which has enabled places like phenix to just be a place that you would desire to live. and so by no means all of it is. i think obviously brian is correct about that, but i do have questions about if we could massively upswing in new york and san francisco, how many people would want to move or would we still see some outmigration for other reasons, for other policy reasons as well? right. it's not all housing. it's it's other things, taxes and so forth. and second, again small empirical quibble because are nowhere near the limit, whatever it is. but high. can we really build? you know, i love brian talks about these giant skyscrapers on central park that take advantage of the view those actually turn out to not be very good buildings and they relate to a well-known problem building which is that elevators are actually huge constraint on how high you can build. so after about 30 floors, residential, this sheer amount of elevator that you need to get to people's their apartments, eating into the apartment value, you get l