You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name 5-[4-(9,9-dimethylfluoren-3-yl)-2,3,3a,8b-tetrahydro-1H-cyclopenta[b]indol-7-yl]thiophene-2-carbaldehyde into its molecular formula.
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C31H27NOS
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