You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 2-(3,4-dichlorophenyl)-N-isoquinolin-4-yl-2-[(2-methoxyacetyl)amino]propanamide by IUPAC nomenclature, provide its molecular formula.
user
C21H19Cl2N3O3
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