You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-[1-(ethylcarbamoyl)-2,3-dihydroindol-6-yl]-5-(3-fluorophenyl)-1,2,4-oxadiazole-3-carboxamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H18FN5O3
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