You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(2R,3R,4S)-2-(6-aminopurin-9-yl)-3-methyl-5-[[4-(2-methylsulfanylpyridin-4-yl)-2-oxo-1,3,2lambda5-dioxaphosphinan-2-yl]oxy]oxolane-3,4-diol is the IUPAC name of a molecule. Please give its molecular formula.
user
C19H23N6O7PS
assistant