You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
ethyl (1R,2R,3R,4S)-3-[5-(4-bromophenyl)-1H-imidazol-2-yl]bicyclo[2.2.1]heptane-2-carboxylate The above is the IUPAC name of a molecule. Write its molecular formula.
user
C19H21BrN2O2
assistant