You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-[[3-(4-chlorophenyl)-1,2,4-oxadiazol-5-yl]methyl]-4-methoxy-3-nitro-N-prop-2-enylbenzamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H17ClN4O5
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