You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
ethyl (1S,10bR)-3-benzoyl-2-methylidene-1,10b-dihydropyrazolo[5,1-a]isoquinoline-1-carboxylate The above is the IUPAC name of a molecule. Write its molecular formula.
user
C22H20N2O3
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