You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-[2-[(4-benzyl-5-methyl-1H-imidazol-2-yl)sulfanyl]acetyl]-2,3-dihydroindole-5-sulfonamide The above is the IUPAC name of a molecule. Write its molecular formula.
user
C21H22N4O3S2
assistant