O=C(c1ccccc1)c1c(C(=O)c2ccccc2)c(-c2ccccc2)c2c(-c3ccccc3)sc(-c3ccccc3)c2c1-c1ccccc1
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.