You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
6-(6-bromo-4-oxo-2-sulfanylidene-4aH-quinazolin-3-yl)-N-(3-propan-2-yloxypropyl)hexanamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H28BrN3O3S
assistant