You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
benzyl N-[(2R)-1-(3,4-dihydro-1H-isoquinolin-2-yl)-1-oxopropan-2-yl]carbamate The above is the IUPAC name of a molecule. Write its molecular formula.
user
C20H22N2O3
assistant