CC(C)(C)OC[C@H](NC(=O)OC(C)(C)C)c1nnc([C@H](CCC(=O)OC(C)(C)C)NC(=O)C2CCN(C(=O)OC(C)(C)C)CC2)o1
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.