You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
ethyl 4-(4-fluorophenyl)-5-methyl-2-[(2-thiophen-2-ylacetyl)amino]thiophene-3-carboxylate The above is the IUPAC name of a molecule. Write its molecular formula.
user
C20H18FNO3S2
assistant