C[C@H]1CC[C@H]2C(=O)N3[C@@H](CC[C@H](C)[C@H]3c3ccccc3Br)C(=O)N2[C@@H]1c1ccccc1Br
PSA is a commonly used medicinal chemistry metric for the optimization of a drug's ability to permeate cells. Please predict psa of this molecule.