You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name 1-acetyl-N-(furan-2-ylmethyl)-2-methyl-N-pyridin-2-yl-2,3-dihydroindole-5-sulfonamide into its molecular formula.
user
C21H21N3O4S
assistant