You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-benzothiophen-3-yl-(4-ethyl-2,3,3a,4,6,6a-hexahydro-1H-pyrrolo[3,4-c]pyrrol-5-yl)methanone is the IUPAC name of a molecule. Please give its molecular formula.
user
C17H20N2OS
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