David Letterman paid tribute to his hero Johnny Carson on Monday's Late Show by delivering a monologue that was composed entirely of jokes the late-night legend had sent him in his final months. Among the topics Carson couldn't resist riffing on via Letterman: Donald Trump's hair, Paris Hilton's missing dog Tinkerbell and John Kerry's military record. Letterman said getting a call from Carson with jokes was "like Christmas morning, for god's sake." He added that all talk-show hosts owe their careers to Johnny. "The reason we're all doing Johnny's Tonight is because you think, 'Well, if I do Johnny's Tonight Show, maybe I'll be a little like Johnny and people will like me more,'" he said. "But it sadly doesn't work that way. It's just, if you're not Johnny, you're wasting your time."