O=[N+]([O-])c1ccc(N2CCC(CCCC3CCN(c4ccc([N+](=O)[O-])cc4[N+](=O)[O-])CC3)CC2)c([N+](=O)[O-])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.