You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-benzyl-2-methoxy-4-(4-methylpiperazin-1-yl)-2,5-dihydropyrido[3,2-d]pyrimidin-8-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H25N5O2
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