You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 1-(3-ethyl-2-morpholin-4-ylpentyl)-2-methyl-3-[3-(3-propan-2-yl-1,2,4-oxadiazol-5-yl)propyl]guanidine by IUPAC nomenclature, provide its molecular formula.
user
C21H40N6O2
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