You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 3-(4-amino-5-fluoropyrrolo[2,3-d]pyrimidin-7-yl)-5-[(6-bromo-1,2,3,4-tetrahydroisoquinolin-8-yl)oxy]cyclopentane-1,2-diol by IUPAC nomenclature, provide its molecular formula.
user
C20H21BrFN5O3
assistant