You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 1-[3-(4-ethylpiperazin-1-yl)-2-methylpropyl]-3-[3-(2-methoxyethoxy)propyl]-2-methylguanidine by IUPAC nomenclature, provide its molecular formula.
user
C18H39N5O2
assistant