COC(=O)c1csc([C@@H](OC(=O)[C@H](C)[C@H](CCCC(C)(Cl)Cl)OC(=O)c2csc([C@H](O)CO)n2)C(C)C)n1
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.