You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Under IUPAC nomenclature, a molecule named 1-azaspiro[3.3]heptan-1-yl-[(1R,5S)-3-[5-(3-methyl-1,2,4-oxadiazol-5-yl)-2-oxa-5-azabicyclo[2.2.2]oct-1(6)-en-7-yl]-3-azabicyclo[3.1.0]hexan-6-yl]methanone is given. What is its corresponding molecular formula?
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C21H27N5O3
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