You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule 2-[3-(2-cyanopropan-2-yl)-5-[1-(1,2,4-triazol-1-yl)ethyl]phenyl]-2-methylpropanenitrile into molecular formula.
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C18H21N5
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