You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(6R,7S)-3-(acetyloxymethyl)-7-[(4-cyanobenzoyl)amino]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid The above is the IUPAC name of a molecule. Write its molecular formula.
user
C18H15N3O6S
assistant