You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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2-[5,6-dichloro-1-(methoxymethyl)-4,9-dihydro-3H-pyrano[3,4-b]indol-1-yl]acetic acid The above is the IUPAC name of a molecule. Write its molecular formula.
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C15H15Cl2NO4
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