CC(=O)O[C@H]1CC2C(C3CC[C@H](C(C)CCC(=O)O)[C@]31C)[C@H](OC(C)=O)C[C@@H]1CC3(CC[C@]21C)OOC1(CCC(C)CC1)OO3
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.