COc1ccc(-c2cc(-c3ccco3)c(C#N)c(=S)n2C2OC(COC(C)=O)C(OC(C)=O)C(OC(C)=O)C2OC(C)=O)cc1
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.