You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
methyl (1R,2S,3R,5S)-8-methyl-3-phenacyl-8-azabicyclo[3.2.1]octane-2-carboxylate The above is the IUPAC name of a molecule. Write its molecular formula.
user
C18H23NO3
assistant