You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-[(1R)-1-(3,4-dichlorophenyl)-3-(methylamino)propyl]-2-(propan-2-ylamino)-6,8-dihydro-5H-pyrido[3,4-d]pyrimidine-7-carboxamide The above is the IUPAC name of a molecule. Write its molecular formula.
user
C21H28Cl2N6O
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