You are a chemist. Now you are given a description of a molecule. Please generate a molecule that meets the description.
system
I need a molecule that meets the following conditions: It belongs to the p2x3 antagonist class of molecules. Please represent the molecule in SMILES.
user
CC(=O)N(C)C1CN(C(=O)NC(C)c2cnc(C(F)(F)F)nc2)N=C1c1ccc(C)cc1
assistant