Extremal Cata-Condensed Benzenoids with Two Full-Hexagons with Respect to the Mostar indices

The Mostar index Mo(G) is the sum of absolute values of the differences between nu(e) and nv(e) over all edges e=uv of G, where nu(e) and nv(e) are the number of vertices of G lying closer to vertex u than to vertex v and the number of vertices of G lying closer to vertex v than to vertex u, respectively. In this article, for given cata-condensed hexagonal systems with p hexagons, which have exactly two full-hexagons, we determine the extremal hexagonal system with the greatest Mostar index, and the corresponding formula of Mostar index is given.