You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
9-(4-methyl-1,3-thiazole-5-carbonyl)-4-phenyl-1-oxa-4,9-diazaspiro[5.5]undecan-3-one The above is the IUPAC name of a molecule. Write its molecular formula.
user
C19H21N3O3S
assistant