You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-O-tert-butyl 3-O-ethyl (1S,3S,5R)-5-(methylsulfonyloxymethyl)-2-azabicyclo[3.1.0]hexane-2,3-dicarboxylate is the IUPAC name of a molecule. Please give its molecular formula.
user
C15H25NO7S
assistant