You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Can you give the molecular formula of the molecule (2S)-2-[[2-(5,6-dimethyl-4-oxo-3-prop-2-enylthieno[2,3-d]pyrimidin-2-yl)sulfanylacetyl]amino]-N-ethylpropanamide ?
user
C18H24N4O3S2
assistant