CC1(C)OC2CC(=O)OC[C@@]23C1CC(=O)[C@]1(C)C3CC[C@@]2(C)C(c3ccoc3)OC(=O)C3O[C@@]321
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.