You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
ethyl (3S)-3-(4-bromophenyl)-3-[2-(2-ethyl-1,3-thiazol-4-yl)acetyl]oxypropanoate The above is the IUPAC name of a molecule. Write its molecular formula.
user
C18H20BrNO4S
assistant