You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
What is the molecular formula of the molecule identified by 1-ethyl-2-[(3-methyl-4-methylsulfonylphenyl)methyl]-3-(2-methyl-2-thiophen-2-ylpropyl)guanidine ?
user
C20H29N3O2S2
assistant