You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 2-(5-chlorothiophen-2-yl)-1-[(2S)-2-(2-methylpyrazol-3-yl)piperidin-1-yl]ethanone by IUPAC nomenclature, provide its molecular formula.
user
C15H18ClN3OS
assistant