Initial sprint velocity problem

On February 14th 2017 I was event host Banja Luka Scrum Meetup (held at ICBL) where I narrated about the initial sprint velocity problem in Scrum. The question is how to determine velocity for the initial sprint? Management wants to know estimates upfront, and past data is not available. What are the options in described situation?

More info in Medium article and Slideshare presentation.