You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named imidazo[1,2-a]pyrimidin-2-yl-[(1S,5R)-4'-methylsulfonylspiro[8-azabicyclo[3.2.1]octane-3,2'-morpholine]-8-yl]methanone by IUPAC nomenclature, provide its molecular formula.
user
C18H23N5O4S
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