Definition: 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.
Input: The Doctor:  Two thousand people on this ship , _ six _ billion underneath us , all of them slaughtered , and why ? Because Max Capricorn is a loser !
Max Capricorn: I never lose !
The Doctor: You ca n't even sink the Titanic !

people