You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name tert-butyl N-[[7-(2-aminoethyl)-5-methyl-2-oxa-7-azaspiro[3.5]nonan-9-yl]methyl]carbamate into its molecular formula.
user
C16H31N3O3
assistant