You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-[[(3R)-1-[3-[(3R)-3-[[ethyl(methyl)amino]methyl]pyrrolidin-1-yl]pyrazin-2-yl]pyrrolidin-3-yl]methyl]-N-methylethanamine The above is the IUPAC name of a molecule. Write its molecular formula.
user
C20H36N6
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