5. Penguin Airlines

namespace _04.FourthTask
{
    using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Text;
    using System.Threading.Tasks;

    public class Program
    {
        public static void Main()
        {
            int n = int.Parse(Console.ReadLine());
            StringBuilder strB = new StringBuilder();
            Dictionary<int, HashSet<int>> dic = new Dictionary<int, HashSet<int>>();
            for (int i = 0; i < n; i++)
            {
                dic.Add(i, new HashSet<int>());
                string input = Console.ReadLine();
                if (input == "None")
                {
                    dic[i].Add(-1);
                }
                else
                {
                    int[] str = input.Split().Select(int.Parse).ToArray();
                    foreach (int number in str)
                    {
                        dic[i].Add(number);
                    }
                }
            }

            string inputT = Console.ReadLine();
            while (inputT != "Have a break")
            {
                int[] inputToN = inputT.Split().Select(int.Parse).ToArray();
                if (dic[inputToN[0]].Contains(inputToN[1]))
                {
                    strB.AppendLine("There is a direct flight.");
                }
                else
                {
                    strB.AppendLine("No flights available.");
                }

                inputT = Console.ReadLine();
            }

            Console.WriteLine(strB.ToString());
        }
    }