as he prepared to tour, warming up with some surprise shows, including this one, at liverpool's cavern clubes played this club almost 300 times, and while mccartney's fans know every word to "hey jude," "yesterday," and "band on the run," we were surprised who didn't-- >> mccartney: when i'm doing shows, i listen to a lot of music, beatles music, wings music, to see what ones we're going to do. and to learn them. >> alfonsi: yeah. what do you mean, you've forgotten them? >> mccartney: yeah. >> alfonsi: really? >> mccartney: there's too many. too many words. ( laughs ) too many notes. they're very hard. i mean, you know, it's not like they're all three chords. >> ♪ i'll pretend that i'm kissing the lips i am missing ♪ >> alfonsi: mccartney is at least a co-author of rock and roll's constitution. >> ♪ maybe i'm amazed at the way you-- >> alfonsi: credited with a stunning 29 number-one hits-- >> ♪ you write me when i'm wrong >> mccartney's work has been covered by icons from almost every musical genre. >> ♪ you and me-- >> alfonsi: famously, john lennon and paul mccartney became songwriting pa