BQ76920: What should I do with an unused cell pin?

Part Number:BQ76920

Hello,

recently there was a post about the minimum amount of cells that should be connected to this chip. I read that it is recommended, to use more than 2 cells. The BQ76920 is designed to use 5 cells.

In my case Im having a battery, which has 4 cells in series, so I think this should be also okay, I guess? 

My question is, what should I do with the input pin which is not connected with a cell? Should I connect it to ground, leave it unconnected or should I do something else with this pin?

Thanks for helping.