1) Guess how many beans (hours) are in the jar (sprint).

2) Pad my estimate with 12 beans.

3) Be high and have to have meetings in which I explain bean counting is not an exact science and insist that meetings about how we count beans will only put us behind further and will never ever make us better bean counters.

or

3b) Be under, have extra time in the sprint, only to have product management fill the jar with more beans until I'm wrong again.