static void Main(string[] args)
        {

            StreamReader read = new StreamReader("C:\\...\\new_file.txt");
            string max = read.ReadLine();
            while (!read.EndOfStream)
            {
                string s = read.ReadLine();

                if (max.Length < s.Length)
                {
                    max = s;
                }
            }
            read.Close();
            Console.WriteLine(max.Length);



        }