You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
[(2R,3S,4R,5R)-5-[2-chloro-4-[1-(4-methylphenyl)ethylamino]pyrrolo[2,3-d]pyrimidin-7-yl]-3,4-dihydroxyoxolan-2-yl]methoxymethylphosphonic acid is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H26ClN4O7P
assistant