You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
methane;6-methyl-2-propan-2-yl-2,6-diazaspiro[3.3]heptane;1-methyl-7-propan-2-yl-1,7-diazaspiro[3.4]octane;5-methyl-2-propan-2-yl-2,5-diazaspiro[3.4]octane;5-methyl-8-propan-2-yl-2-oxa-5,8-diazaspiro[3.5]nonane;6-propan-2-yl-1-oxa-6-azaspiro[3.3]heptane;6-propan-2-yl-2-oxa-6-azaspiro[3.3]heptane;7-propan-2-yl-1-oxa-7-azaspiro[4.4]nonane;7-propan-2-yl-2-oxa-7-azaspiro[4.4]nonane;2-propan-2-yl-5-oxa-2-azaspiro[3.4]octane;2-propan-2-yl-6-oxa-2-azaspiro[3.4]octane;7-propan-2-yl-1-oxa-7-azaspiro[3.4]octane;7-propan-2-yl-2-oxa-7-azaspiro[3.4]octane is the IUPAC name of a molecule. Please give its molecular formula.
user
C131H255N19O10
assistant