Hey guys im a big mini casino player and i am working on a balance map. I was wondering how do i limit the number of base defenses? So far i have tried a few things and nothing works

if
player0 has greater than or equal to 2 base defenses
and true
then
usa fire base unbuildable
else
usa fire base buildable

this does nothing but if i take out the action if false "usa fure base buildable" it will delete firebase from being able to be built but i cant figure out how to make it buildable again

i have tried other ways to and im reading into subroutines but like i said this is my first time doing this and im not sure what im doing

any help much appreciated