You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-(4-chlorophenyl)-7-(2-methylpropyl)-3,5,6,8-tetrahydropyrido[3,4-d]pyrimidin-4-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C17H20ClN3O
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