You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(NE,R)-N-[(2R,3'S)-6-bromo-3'-ethylspiro[3H-indene-2,1'-cyclohexane]-1-ylidene]-2-methylpropane-2-sulfinamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H28BrNOS
assistant