C=C1C(=O)O[C@H]2C1[C@H](OC(=O)/C(C)=C\COC(C)=O)C[C@]1(CO1)[C@@H]1[C@H](O)[C@H]3O[C@@]3(C)[C@H]21
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.