You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named N-[(3-cyano-6-methyl-4,5,6,7-tetrahydro-1-benzothiophen-2-yl)carbamothioyl]butanamide by IUPAC nomenclature, provide its molecular formula.
user
C15H19N3OS2
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