You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-(2,6-diazaspiro[3.5]nonan-6-yl)-2-methyl-2-[2-(2-methylpyridin-4-yl)-3-propan-2-yl-1H-indol-5-yl]propan-1-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C28H36N4O
assistant