You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-(2,2-diethyl-4-hydroxybutyl)-2-[[2-(difluoromethoxy)-5-methoxyphenyl]methyl]-3-ethylguanidine is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H33F2N3O3
assistant