CCCC(=O)Nc1ncnc2c1ncn2[C@@H]1O[C@@H]2COP(=O)([O-])O[C@H]2[C@H]1OC(=O)CCC.[Na+]
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.