You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-ethyl-3-[(1-hydroxycyclobutyl)methyl]-2-[[2-(3-methoxypropoxy)-4-methylphenyl]methyl]guanidine is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H33N3O3
assistant