You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name 1-[2-[(R)-cyclobutyl(hydroxy)methyl]-4,6,7,8-tetrahydropyrazolo[1,5-a][1,4]diazepin-5-yl]-2-(cyclopropylmethylsulfanyl)ethanone into its molecular formula.
user
C18H27N3O2S
assistant