Thank you very much! I did the same computation you did and I wanted to be as ... mathematical as possible. I never guessed the lottery. The big challenge was to determine the volume of a coffee bean as much as possible (in the house I have only ground coffee).
I'm surprised I was still so close! I think I should still try the lottery ... maybe something has changed with my luck.
Congratulations to all participants, to those who gave the correct answer and thousands of thanks to the contest initiator, @c0ff33a.