You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Under IUPAC nomenclature, a molecule named 1-(3,4-dihydro-2H-chromen-4-yl)-2-methyl-3-(2-thiophen-2-ylpropyl)guanidine is given. What is its corresponding molecular formula?
user
C18H23N3OS
assistant