How many House Democrats does Pelosi need to keep her position as Speaker?

[I spent the winter writing songs about getting better]

Does each party of a Speaker "primary" first, or is it more everyone for themselves in an open race?

I think it's just like a convention race, a majority is needed, everyone runs, if no one gets a majority someone likely drops out and another vote is held until someone does.

[I spent the winter writing songs about getting better]

I'm talking about election for the leader of the party. Who then becomes who they vote for Speaker. I think Speaker requires a majority of the House too so if one can't acheive it the majority party has to elect someone else as leader. There was some controversy in 1999 I believe because it looked like Gingrich might not have got the votes to be elected Speaker, about seven or so Republicans declined to vote for him but he still got the votes needed.