Most Frequent Number

            char[] separators = new char[] { ' ', ';' };
            string[] sentence = Console.ReadLine().Split(separators, StringSplitOptions.RemoveEmptyEntries);

            var query = (from i in sentence
                         group i by i into g
                         orderby g.Count() descending
                         select new { Key = g.Key, Count = g.Count() }).FirstOrDefault();

            if (query == null)
            {
                Console.WriteLine("query = NULL");
            }
            else
            {
                Console.WriteLine("{0}", query.Key);
            }