To further analyze the convergence with respect to the QM size, Fig. shows the number of hydrogen bonds formed by the water molecules of the first solvation shell as a function of the QM size for the same snapshot as used in Fig. . As one can see, beyond the QM size of 10, the protocol based on the distance from the first solvation shell captures more hydrogen bonds than the protocol based on the distance from the central water. We also see that all bonds are captured for a smaller QM size when QM is selected using the former protocol: saturation is reached at 15 waters versus 18. On the basis of this analysis, we conclude that the QM size of 20 waters should be sufficient to capture all hydrogen bonds formed by the first solvation shell and we use QM size of 20 waters in our production-level calculations. f Same as e, but including MM charges.