Glenn, George, and others in the G.B. crew

There are two laureates with Berkeley, California as a prize affiliation city that have the initials G.S. - Glenn Seaborg and George Smoot. How many laureates in total have a first name beginning with "G" and a surname beginning with "S"?

Evaluate the expression

db.laureates.count_documents({"firstname": Regex(____), "surname": Regex(____)})

in the console, filling in the blanks appropriately.