A majority of the House is 218 members — but that number is not always required to elect a Speaker.

The Speaker is elected by a majority of all members present and voting for a candidate — not counting “present” votes and absences.

With 434 incoming members and one vacancy, that number is 218 if all members vote. But if one member votes “present” or is absent, that number is lowered to 217. If three members are absent or vote “present,” that number lowers to 216.

Former Speakers Nancy Pelosi (D-Calif.) and John Boehner (R-Ohio) were each elected with only 216 votes in 2021 and 2015, respectively.

Three members were absent during the 12th Speaker ballot on Friday morning, meaning the number to win would have been 216. And with Rep. Kevin McCarthy (R-Calif.) flipping 13 of his 20 detractors to support him in that ballot, he got up to 213 votes, just three votes shy of getting the gavel.

Rep. David Trone (D-Md.) was absent on Friday for the 12th Speaker ballot due to a previously scheduled surgery, his spokesperson said in a statement. But he was back at the Capitol by 2 p.m. for the next ballot, he said in a tweet.

Trone’s move to rush back to the Capitol illustrates the importance of the Speaker math. His return to the Capitol for the 13th vote ticked the majority threshold up to 217.

Those two other absences are GOP McCarthy supporters. Rep. Ken Buck (Colo.) reportedly flew to Colorado for a medical procedure on Thursday, and Rep.-elect Wesley Hunt (Texas) flew to Texas to be with his family after his son was born prematurely a few days ago.

Some reports said Buck is expected to be back in Washington later this evening. But even if both Buck and Hunt return to vote for McCarthy, he will need to either flip two of the six GOP holdouts or convince several of them to vote “present.”

If the House extends voting until Saturday, McCarthy could lose another supporter due to absence. Rep. Kevin Hern (R-Okla.) will be attending a funeral for his mother.