You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-[2-methoxy-4-(4-methylpiperazin-1-yl)anilino]-5-methylpyrimido[4,5-b][1,4]benzoxazepin-6-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C24H26N6O3
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