You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-amino-8-(1-methyl-6-pyridin-4-ylpyrazolo[3,4-d]pyrimidin-4-yl)-1,3,8-triazaspiro[4.5]dec-1-en-4-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C18H19N9O
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