You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name 2-[(3R)-1-(2,5-dimethylphenyl)-2,5-dioxopyrrolidin-3-yl]sulfanylpyridine-3-carboxylic acid into its molecular formula.
user
C18H16N2O4S
assistant