You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named (4R)-2-(4-ethylpiperazin-4-ium-1-yl)-N-(3-methoxyphenyl)-6-oxo-4,5-dihydro-1H-pyrimidine-4-carboxamide by IUPAC nomenclature, provide its molecular formula.
user
C18H26N5O3+
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