You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule 3-methoxy-4-methylthiophene;2-(2-sulfanylethylsulfanyl)ethanethiol;2,3,5,6-tetrahydrothieno[3,4-b][1,4,7]trithionine into molecular formula.
user
C18H28OS8
assistant