Cl.O=C1/C(=C/c2ccc(Cl)c(Cl)c2)CN(C(=O)CCN2CCOCC2)C/C1=C\c1ccc(Cl)c(Cl)c1
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.