Middle European Mathematical Olympiad 2019 Problem I-2
Let be an integer. We say that a vertex () of a convex polygon is Bohemian if its reflection with respect to the midpoint of the segment (with and ) lies inside or on the boundary of the polygon . Determine the smallest possible number of Bohemian vertices a convex -gon can have (depending on ).
(A convex polygon has vertices with all inner angles smaller than .)