COC(=O)[C@H]1C=C[C@H](OC2OC(COC(C)=O)C(OC(C)=O)C(OC(C)=O)C2OC(C)=O)n2c(=O)n(-c3ccccc3)c(=O)n21
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.