You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-(4-ethoxyphenyl)-2-[[4-methyl-5-(5-methylthiophen-3-yl)-1,2,4-triazol-3-yl]sulfanyl]acetamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C18H20N4O2S2
assistant