You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-ethyl-2-[[1-(2-hydroxyethyl)cyclohexyl]methyl]-3-[3-(3-methylpiperidin-1-yl)-3-oxopropyl]guanidine;hydroiodide is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H41IN4O2
assistant