C=C1[C@H](OCC(C)C)[C@@H](OCC(C)C)[C@@H](O)C(C)(C)/C=C/[C@H](C)C(=O)[C@@]2(O)C[C@H](C)[C@H](O)[C@@H]2[C@H]1OCC(C)C
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.