You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-[4-(cyclopropanecarbonyl)piperazin-1-yl]-N-[(4-fluorophenyl)-thiophen-2-ylmethyl]acetamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H24FN3O2S
assistant