Given the task definition and input, reply with output. In this task, you will use your knowledge about language (and common sense) to determine what element the marked number refers to. The numbers are marked with two underlines around them, like: _ number _. Your answer should be chosen from the given text, and should not contain other words.

The Doctor: Why are you repeating ?
Sky Silvestry: Why are you repeating ?
The Doctor: What is that , learning ?
Sky Silvestry: What is that , learning ?
The Doctor: Copying ?
Sky Silvestry: Copying ?
The Doctor: Absorbing ?
Sky Silvestry: Absorbing ?
The Doctor: The square root of pi is _ 1.7 _ ...
Sky Silvestry: The square root of pi is ...
The Doctor: 7245385090 ...
Sky Silvestry: 1.77245385 ...
The Doctor: 551602729 ...
Sky Silvestry: 90551602 ...
The Doctor: 816748334 ...
Sky Silvestry: 729816748 ...
The Doctor: 1 . Wow .
Sky Silvestry: 3341 . Wow .
Professor Hobbes: But
Professor Hobbes: that 's impossible .
Sky Silvestry: But that 's impossible .
Dee Dee Blasco: She could n't repeat all that .
Sky Silvestry: She could n't repeat all that .
Val Cane: Tell her to stop .
Sky Silvestry: Tell her to stop .
root