You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
4-[3-(3-methoxypyrazin-2-yl)oxypyrrolidine-1-carbonyl]-1-(oxan-4-yl)pyrrolidin-2-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C19H26N4O5
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