You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Can you give the molecular formula of the molecule 2-[4-[7-bromo-3,9-dioxo-2-(1,3,4-thiadiazol-2-yl)-1H-chromeno[2,3-c]pyrrol-1-yl]phenoxy]acetamide ?
user
C21H13BrN4O5S
assistant