You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-[2-[3-[[(S)-methylsulfinyl]methyl]anilino]-2-oxoethyl]-1,3-dihydroindene-2-carboxylic acid The above is the IUPAC name of a molecule. Write its molecular formula.
user
C20H21NO4S
assistant