determining # of moles from volume

[dontunderstand]

A sample of neon at 25°C occupies a volume of 500. L at 2.00 atm. How many moles of neon are present?

I set it up like : (2.0atm*500L)/(.0821 mol*298K)=1000/24.47=40.87

But this answer was wrong. Can someone show me what I am doing wrong?

/thanks