You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
3-[(3E,7E,11E,15E,18E)-4,8,12,16-tetramethylicosa-3,7,11,15,18-pentaenyl]thiophene The above is the IUPAC name of a molecule. Write its molecular formula.
user
C28H42S
assistant