You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-[(4R)-2,2-dimethyl-4-(2-methylphenyl)oxan-4-yl]-N-[(4-methylthiadiazol-5-yl)methyl]acetamide The above is the IUPAC name of a molecule. Write its molecular formula.
user
C20H27N3O2S
assistant