You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Under IUPAC nomenclature, a molecule named [2-chloro-4-[(5-fluoro-1-benzofuran-7-yl)oxy]phenyl]-(4-chloro-7H-pyrrolo[2,3-d]pyrimidin-5-yl)methanone is given. What is its corresponding molecular formula?
user
C21H10Cl2FN3O3
assistant