You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Provide the molecular formula for the IUPAC named substance pentasodium;[(1S,2R,4R,5R)-3-[[(2R)-2-butanoyloxy-3-octadecanoyloxypropoxy]-oxidophosphoryl]oxy-2,4,6-trihydroxy-5-phosphonatooxycyclohexyl] phosphate .
user
C31H56Na5O19P3
assistant