O=C(NN1C(=O)c2ccc(-c3ccc4c(c3)C(=O)N(NC(=O)c3cccnc3)C4=O)cc2C1=O)c1cccnc1
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.