O=C(Nc1nc2ccc(SC(F)F)cc2s1)c1ccc(NS(=O)(=O)c2ccc(F)c(F)c2)cc1
An acid's negative base-10 logarithmic dissociation constant (pka) follows directly from its underlying thermodynamics; pKa is directly proportional to its standard Gibbs free energy change. What is the pka value of this molecule?