You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
tert-butyl N-[1-[N'-[2-(dimethylamino)-2-(furan-2-yl)ethyl]-N-ethylcarbamimidoyl]pyrrolidin-3-yl]carbamate is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H35N5O3
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