You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(2R,3R)-1-(2,2-dimethyl-10,10-dioxo-10lambda6-thia-9-azatricyclo[6.3.0.03,6]undecan-9-yl)-3-methoxy-2-methylhept-6-en-1-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H33NO4S
assistant