Number of faces of $n$ congruent disks

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If I have $n$ disks, all of the same radius, how many faces (i.e. maximally connected regions) can the induced arrangement have? For example for 3 disks, it could have 7 bounded faces, but what is the asymptotic dependence on $n$?

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Viewing the disks as circles, if each one intersects each of the others, you get a graph with $n(n-1)$ vertices, all of degree $4$, so $2n(n-1)$ edges, so, by $v-e+f=1$, $n(n-1)+1$ faces.

That would be an upper bound, as I'm not certain it can be arranged that each pair of disks has an overlap.