You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Provide the molecular formula for the IUPAC named substance 2,3,4,5,6-pentamethylpyridine;2,3,5,6-tetramethylpyrazine;2,4,5,6-tetramethylpyrimidine;2,3,4,5-tetramethylthiophene .
user
C78H117N11S2
assistant