You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named N-[3-[[(6Z,12E)-18-hydroxy-2,8-dioxo-3-oxabicyclo[12.4.0]octadeca-1(14),6,12,15,17-pentaen-16-yl]oxy]propyl]methanesulfonamide;dihydrate by IUPAC nomenclature, provide its molecular formula.
user
C21H31NO9S
assistant