You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
3-ethyl-2-[3-[ethyl(methylsulfonyl)amino]propyl]-1-methyl-1-[(1-methylpyrrol-2-yl)methyl]guanidine The above is the IUPAC name of a molecule. Write its molecular formula.
user
C16H31N5O2S
assistant