You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Provide the molecular formula for the IUPAC named substance 1-[(2S,4S)-4-[2-(3,4-dihydro-1H-isoquinolin-2-yl)-2-oxoethyl]-5-oxopyrrolidine-2-carbonyl]pyrrolidine-2-carbonitrile .
user
C21H24N4O3
assistant