You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
[[(2S)-2-[(1R)-1-(6-aminopurin-9-yl)-2-oxoethoxy]-3-oxopropoxy]-hydroxyphosphoryl] [[[(2R)-2-[(1R)-1-(6-aminopurin-9-yl)-2-oxoethoxy]-3-oxopropoxy]-hydroxyphosphoryl]oxy-hydroxyphosphoryl] hydrogen phosphate is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H24N10O19P4
assistant