You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 1-cyano-3-methyl-N-(4,5,6,7-tetrahydro-1-benzothiophen-4-yl)cyclobutane-1-carboxamide by IUPAC nomenclature, provide its molecular formula.
user
C15H18N2OS
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