You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Can you give the molecular formula of the molecule 4-[3-[6-cyano-5-(trifluoromethyl)pyridin-3-yl]-5-ethyl-5-methyl-4-methylidene-2-sulfanylideneimidazolidin-1-yl]-2-fluorobenzoic acid ?
user
C21H16F4N4O2S
assistant