You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
[(3R,4R)-3-[[2-hydroxyethyl(methyl)amino]methyl]-4-(hydroxymethyl)pyrrolidin-1-yl]-naphthalen-1-ylmethanone The above is the IUPAC name of a molecule. Write its molecular formula.
user
C20H26N2O3
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