You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Please write the molecular formula of the molecule 1-[4-[[5-(cyclopropanecarbonyl)spiro[6,7-dihydro-1H-imidazo[4,5-c]pyridine-4,4'-piperidine]-1'-yl]methyl]thiophen-2-yl]ethanone .
user
C21H26N4O2S
assistant