You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule 4-[5-(1-methylpyrazol-4-yl)-3-[2-(1-methylpyrazol-4-yl)ethyl]imidazol-4-yl]benzonitrile into molecular formula.
user
C20H19N7
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