O=C(OCc1cn([C@@H]2C[C@H](c3ccccc3)N(C(=O)c3cccs3)C[C@H]2O)nn1)c1ccccc1
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?