You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-[4-(1-acetyl-2,3-dihydroindol-5-yl)-1,3-thiazol-2-yl]-2-methoxybenzamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H19N3O3S
assistant