You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named N-[2-(2-fluorophenyl)-2-methylpropyl]-4-(furan-2-carbonyl)-N'-methylpiperazine-1-carboximidamide by IUPAC nomenclature, provide its molecular formula.
user
C21H27FN4O2
assistant