was looking up someone in a phone book.

Well, here I have a pretty thick yellow pages wherein

there's a whole bunch of products and services alphabetized from A to Z.

And we can, of course, look up the number for someone in this book.

For instance, suppose today we need a plumber.

Could we ask Mariano to find us a plumber in this phone book?

Flipping through a few pages.

A lot of pages.

Yeah.

OK.

All right.

And we have a page full of plumbers.

And now, could your dad have done better do you think?

DANIELLA: Yes.

DAVID MALAN: I think so.

So would you like to show dad and other parents here

what you might have done instead?

Oh my goodness.

[LAUGHTER]

OK.

Thank you.

[APPLAUSE]

[LAUGHTER]

DAVID MALAN: And for those wondering, let's continue the algorithm,

if you will.

What's your next step?

[LAUGHTER]

Nice.

And why are you doing this, though?

DANIELLA: So I open halfway and then if it's not on the page

and it looks like, for example, if it's n, I know p is afterwards.

So I need to get rid of the first half and just look at the second half.

DAVID MALAN: Well, need to is a little strong.

[LAUGHTER]

But you can get rid of--

yes, indeed.

So if you keep this process going, halving, and halving, and halving,

what should you be left with ultimately?

DANIELLA: Just the letter p.

DAVID MALAN: Just the letter p.

Round of applause would be good for both of our volunteers here.

[APPLAUSE]

DAVID MALAN: Thank you.