Cc1nc(N)c2ncn([C@@H]3O[C@H](CS)[C@@H](OP(=O)([O-])OP(=O)([O-])OP(=O)([O-])[O-])[C@H]3O)c2n1.[Na+].[Na+].[Na+].[Na+]
Molecules with a polar surface area of greater than 140 angstroms squared (Å2) tend to be poor at permeating cell membranes. What's the psa of this molecule?