and so what we get to do is say, okay, let's go over to that skyscraper, let's figure out who's inside the building, then let's call up all those companies, let's figure out how much they're paying. >> what their secretary footage is? >> what their square footage is. boot over boot measure one end to the other end. >> did you think when you were going to start looking into trump's conflicts you would basically going to be -- >> a vagabond wandering around his properties? no, i did not imagine. it's absurd but this is the way you have to figure out who's paying the president of the united states. >> dan and his colleagues use their findings, along with bank records and market rates, to reconstruct the rent rules for donald trump's biggest properties. >> we counted up more than 80 tenants, and of those, 36 of them had very clear ties with the federal government. whether it was that they were contractors or that they were under investigation by the federal government. so right there that's three dozen, okay? that's just the tenants. >> according to "forbes" and