O=C(NC1=C(Cl)C(=O)c2ccccc2C1=O)C(=O)C(C(=O)c1ccc2ccccc2c1)C1OC(=O)c2ccccc21
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.