You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-(4,5-dichloro-2-fluorophenyl)-7-[2-(2-fluoroethoxy)ethoxy]-6-nitroquinazolin-4-amine is the IUPAC name of a molecule. Please give its molecular formula.
user
C18H14Cl2F2N4O4
assistant