You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
[5-(4-bromophenyl)pyrazolidin-3-yl]-(3,4-dihydro-1H-isoquinolin-2-yl)methanone The above is the IUPAC name of a molecule. Write its molecular formula.
user
C19H20BrN3O
assistant