public string CountRoutesExactlyStops(Node start, Node end, int exactlyStops)
        {
            var filter = CountRoutesFilter.ExactlyStops(this._graph, start, end, exactlyStops);

            return(GetCountRoutes.Execute(filter).ToString());
        }
        public string CountRoutesMaxCost(Node start, Node end, int maxCost)
        {
            var filter = CountRoutesFilter.MaxCost(this._graph, start, end, maxCost);

            return(GetCountRoutes.Execute(filter).ToString());
        }