You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
4-[2-chloro-4-(dimethylamino)-5-fluorophenyl]-2-N-(1-cyclopropylethyl)pyridine-2,3-diamine The above is the IUPAC name of a molecule. Write its molecular formula.
user
C18H22ClFN4
assistant