O=c1[nH]c(-c2ccc(-c3nc4cc([N+](=O)[O-])ccc4c(=O)[nH]3)cc2)nc2cc([N+](=O)[O-])ccc12
Molecules with a polar surface area of greater than 60 angstroms squared (Å2) is hard to pass brain blood barrier. What's the psa of this molecule?