You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Convert the IUPAC name of a molecule 12-butylspiro[4-oxa-11-azatetracyclo[11.4.0.01,5.06,11]heptadeca-5,9,12-triene-3,4'-imidazolidine]-2'-one;hydrochloride into molecular formula.
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C21H30ClN3O2
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