You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name (5S,7R)-5,7-dimethyl-1-prop-2-enyl-3-aza-1-azoniatricyclo[3.3.1.13,7]decan-6-one into its molecular formula.
user
C13H21N2O+
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