CC1(C)C2CCC1(C)[C@H](n1c(=O)n([C@@H]3CC4CCC3(C)C4(C)C)c(=O)n([C@@H]3CC4CCC3(C)C4(C)C)c1=O)C2
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.