public int Heuristic(int goal, int next)
        {
            string url = $"https://maps.googleapis.com/maps/api/directions/json?origin={_dict[goal]}&destination={_dict[next]}&key=AIzaSyDH2GPpmav9YpqRI3RqIJBR9jgRdWxNeOE";
            WebRequest webRequest = WebRequest.Create(url);
            WebResponse webResponse = webRequest.GetResponse();

            string res = new StreamReader(webResponse.GetResponseStream())
                .ReadToEnd();

            var v = res.Split(new char[] {'{', '}'});
            var fromCoords = v[18]
                .Replace(':', ' ')
                .Replace(" ", "")
                .Replace("\n", "")
                .Replace("\"", " ")
                .Replace(",", "")
                .Replace(".", ",")
                .Split(' ');

            var toCoords = v[20]
                .Replace(':', ' ')
                .Replace(" ", "")
                .Replace("\n", "")
                .Replace("\"", " ")
                .Replace(",", "")
                .Replace(".", ",")
                .Split(' ');

            double [,]matrix=  new double[2,2];
            matrix[0, 0] = Convert.ToDouble(fromCoords[2]);
            matrix[0, 1] = Convert.ToDouble(fromCoords[4]);
            matrix[1, 0] = Convert.ToDouble(toCoords[2]);
            matrix[1, 1] = Convert.ToDouble(toCoords[4]);

            var dist = Math.Pow(matrix[0, 0] - matrix[1, 0], 2) + Math.Pow(matrix[0, 1] - matrix[1, 1], 2);
            return (int) (111 * dist);
        }