2016 is absolutely awesome 13

Probability Level 5

A total of 2016 tickets, numbered 1, 2, 3, 4, ... , 2015, 2016, are placed in an empty bag.

Alberto removes ticket $x$ from the bag. Beck then removes ticket $y$ from the bag. Finally, Chris removes ticket $z$ from the bag.

They notice that $x<y<z$ and $x+y+z=6000$ . In how many ways could this happen?