You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule 2-[[2-(6-fluoro-4-oxo-4aH-quinazolin-3-ium-3-yl)acetyl]amino]-N-prop-2-ynylbenzamide into molecular formula.
user
C20H16FN4O3+
assistant