You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
benzyl (1S,5R)-3-[[(5S)-5-butyl-9-[4-methyl-1-[(2-methylpropan-2-yl)oxycarbonyl]piperidin-4-yl]-2-oxo-1-oxa-3,9-diazaspiro[5.5]undecan-3-yl]methyl]-8-azabicyclo[3.2.1]octane-8-carboxylate is the IUPAC name of a molecule. Please give its molecular formula.
user
C39H60N4O6
assistant