You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(2R,5S)-2-ethyl-5-methyl-3-[methyl(sulfido)phosphoryl]oxyoxolane;[(2R,5S)-2-ethyl-5-methyloxolan-3-yl]oxy-methyl-oxido-sulfanylidene-lambda5-phosphane;3'-hydroxy-6-(8-methoxy-7-methyloctanoyl)-6'-methylspiro[2-benzofuran-3,9'-xanthene]-1-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C63H96O18P4S4-4
assistant