You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
6-bromo-8-cyclopentyl-2-[4-(4-ethylpiperazin-1-yl)anilino]-4-methylpyrido[2,3-d]pyrimidin-7-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C25H31BrN6O
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