You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-[4-(2-chlorophenyl)-2,5-dioxo-1-prop-2-enyl-4,7-dihydro-3H-pyrrolo[3,4-d]pyrimidin-6-yl]-N-prop-2-ynylacetamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H19ClN4O3
assistant