You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name (4aR,9bR)-2-butyl-5-methyl-6-(4-methylphenyl)sulfanyl-3,4,4a,9b-tetrahydro-1H-pyrido[4,3-b]indole into its molecular formula.
user
C23H30N2S
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