You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
4-[2-(furan-2-ylmethylamino)-2-oxoethyl]sulfanyl-N-(2,4,6-trimethylphenyl)butanamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H26N2O3S
assistant