You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
ethyl 2-(1-cyano-3-propyl-5,6,7,8-tetrahydroimidazo[1,5-a]pyridin-8-yl)prop-2-enoate is the IUPAC name of a molecule. Please give its molecular formula.
user
C16H21N3O2
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