You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name 1-[2-(1H-benzimidazol-2-yl)ethyl]-3-[(5-ethylthiophen-2-yl)methyl]-2-methylguanidine;hydroiodide into its molecular formula.
user
C18H24IN5S
assistant