You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named [2,5-dimethyl-1-(5-methyl-1,2-oxazol-3-yl)pyrrol-3-yl]methyl-[3-(2-oxopyrrolidin-1-yl)propyl]azanium by IUPAC nomenclature, provide its molecular formula.
user
C18H27N4O2+
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