You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-[2-(6-chloropyridin-3-yl)ethyl]-2-[2-(dimethylamino)-2-(furan-2-yl)ethyl]-3-ethylguanidine is the IUPAC name of a molecule. Please give its molecular formula.
user
C18H26ClN5O
assistant