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 methyl 4-[[N-ethyl-N'-(naphthalen-2-ylmethyl)carbamimidoyl]amino]piperidine-1-carboxylate is given. What is its corresponding molecular formula?
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C21H28N4O2
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