using System;

public class Program

{

    class Domino {

        public int Left { get; set; }

        public int Right { get; set; }

    }

    public static void Main()

    {

        string[] S = {

            "6-3", 

            "4-3,5-1,2-2,1-3,4-4",

            "1-1,3-5,5-2,2-3,2-4",

            "",

            null,

            "1-1",

            "1-2,1-2",

            "3-2,2-1,1-4,4-4,5-4,4-2,2-1",

            "5-5,5-5,4-4,5-5,5-5,5-5,5-5,5-5,5-5,5-5",

            "1-1,3-5,5-5,5-4,4-2,1-3",

            "1-2,2-2,3-3,3-4,4-5,1-1,1-2"

        };

        for (int i = 0; i < S.Length; i++) {

            domino(S[i]);

        }

    }

    public static void domino(string S)

    {

        int count = 0, max = 0, cur = -1;

        if (!string.IsNullOrEmpty(S)) {

            string[] split = S.Split(',');

            int left = 0, right = 0;

            for (int i = 0; i < split.Length; i++) {

                string[] vals = split[i].Split('-');

                if (vals.Length != 2) {

                    throw new ArgumentException($"Invalid argument found: {split[i]}");

                }

                if (int.TryParse(vals[0], out left) && int.TryParse(vals[1], out right)) {

                    Domino d = new Domino { Left = left, Right = right };

                    if (cur == -1 || d.Left == cur) {

                        count++;

                    }

                    else {

                        if (count > max) { max = count; }

                        count = 1;

                    }

                    cur = d.Right;

                }

                else {

                    throw new ArgumentException($"Invalid domino value: {split[i]}");

                }

            }

            if (count > max) { max = count; }

        }

        Console.WriteLine($"Maximum domino chain in {S}: {max}");

    }

}