Which chemicals from a school chemistry storage room should I kill myself with?

I've already decided to do it, so please just answer the question. The only thing you can do to help me is try and help me figure out which and how much of some chemicals I could find in a chemistry storage room I should take to achieve the fastest and most painless death possible. By the way I already know how to pick the lock on the door, but tips would be useful. Thanks. Please no massive long speeches telling me that life is worth living. And also, please keep in mind that some thing my school won't be licensed to have, so there's no point in suggesting things like "blow yourself up with francium"