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 (1S,11S,12R,16S,20R)-11-ethyl-17-methyl-9,17-diazapentacyclo[10.7.1.02,10.03,8.016,20]icosa-2(10),3,5,7-tetraene is given. What is its corresponding molecular formula?
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C21H28N2
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