From the AIMD simulations, we generated 20,000 configurations for each of the first 9 steps of the thermodynamic integration. For the last step, where γ=1, 50,000 configurations were collected from the two coupled simulations (IS of Na + and Cl -) and one uncoupled simulation (PK), respectively. We trained a model for each step of the TI process (IS and PK, 10 models in total) and another 2 models for the interaction energy calculations over the uncoupled and coupled configurations of the LR simulations, respectively. We also tried to obtain a single NNIP model by using all of the collected AIMD data. This all-in-one model produced an error of magnitude about 3 kcal/mol for the solutesolvent interaction energy compared with the AIMD calculation, and a similar error in the free energy. Due to this relatively large error, we did not utilize the all-in-one method further.