Hopefully it's at least 22. In that case something like this happens (schools can be swapped between the conferences and it doesn't change the point)
B1G (18): UNC, UVA, ND, Miami
SEC (16): FSU, Clemson, NCST, GT, VT, Louisville
That leaves... ACC: BC, Duke, Pitt, Cuse, WF
If the XII can hold onto P3 and they also go to 22 then they need 6 more members. UConn has to hold off Memphis, SMU, SDSU, Tulane, USF, etc to be that number 6. I would hope we are currently ahead of all of these G5 teams and at least BC, Cuse, and WF at this point from the ACC leftovers.
If the number is 20, things get a lot tougher for UConn. We're probably currently the "last team in" in that scenario.