You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
[(2S)-1-[(3,4-dimethoxyphenyl)methylamino]-1-oxopropan-2-yl] 5-ethyl-4-methylthiophene-2-carboxylate is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H25NO5S
assistant