You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2,2,5,5-tetramethyl-N-[2-(2-methyl-4-oxoquinazolin-3-yl)ethyl]-1H-pyrrole-3-carboxamide;dihydrochloride is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H28Cl2N4O2
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