You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named N-(2-propan-2-ylphenyl)-2-(1,2,3,4-tetrahydroisoquinolin-2-ium-2-yl)acetamide by IUPAC nomenclature, provide its molecular formula.
user
C20H25N2O+
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