You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Provide the molecular formula for the IUPAC named substance 3,4-dimethyl-N-[2-oxo-2-[4-(thiophen-2-ylmethyl)piperazin-1-yl]ethyl]benzamide .
user
C20H25N3O2S
assistant