You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(E)-N-[(4aR,6R,8aS)-2,3,4a,5,6,7,8,8a-octahydrobenzo[b][1,4]dioxin-6-yl]-2-phenylethenesulfonamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C16H21NO4S
assistant