You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named (2-amino-1,3-dihydroinden-2-yl)-[3-([1,2,4]triazolo[4,3-a]pyridin-3-yl)piperidin-1-yl]methanone by IUPAC nomenclature, provide its molecular formula.
user
C21H23N5O
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