You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-[2-(2-methoxy-5-methylphenyl)ethyl]-2-methyl-3-[[4-(2-methylpropyl)morpholin-2-yl]methyl]guanidine is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H36N4O2
assistant