CO-MO 2020 Problem 2

Given a regular $n$ -sided polygon with $n \ge 3$ . Maria draws some of its diagonals in such a way that each diagonal intersects at most one of the other diagonals drawn in the interior of the polygon. Determine the maximum number of diagonals that Maria can draw in such a way.

Note: Two diagonals can share a vertex of the polygon. Vertices are not part of the interior of the polygon.