You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named N-[(4S,5R)-9-(2-ethylsulfanylethyl)-5-hydroxy-4-methyl-1-oxa-9-azaspiro[5.5]undecan-4-yl]-3-methyl-1,2-oxazole-5-carboxamide by IUPAC nomenclature, provide its molecular formula.
user
C19H31N3O4S
assistant