Hypothetically speaking, if your death would save the life of one or more complete strangers that you know nothing about, how many people would need to be saved (if any) in order for you to give up your own life?
EDIT: Your death would be painless and instantaneous.
I’d like to think one would be enough (in a vacuum, assuming you have no prior knowledge of the person to make you think they’re a homicidal maniac or something). The maths might not be very Utilitarian, but I think it’s the right thing to do.