static void Solution1()
        {
            int target;
            string[] numStrings;
            Dictionary<int, int> dict = new Dictionary<int, int>();
            using (var sr = File.OpenText("input.txt"))
            {
                target = int.Parse(sr.ReadLine());
                numStrings = sr.ReadLine().Split(new char[] { ' ' });
            }

            foreach (var numStr in numStrings)
            {
                int num = int.Parse(numStr);
                if (num >= target)
                {
                    continue;
                }

                if (dict.ContainsKey(num))
                {
                    dict[num] += 1;
                }
                else
                {
                    dict.Add(num, 1);
                }
            }

            foreach (var pair in dict)
            {
                if (dict.ContainsKey(target - pair.Key)
                    && (pair.Key != target - pair.Key)
                    || (pair.Key == target - pair.Key
                        && pair.Value > 1))
                {
                    using (var sw = File.CreateText("output.txt"))
                    {
                        sw.WriteLine(1);
                        return;
                    }
                }
            }
            using (var sw = File.CreateText("output.txt"))
            {
                sw.WriteLine(0);
            }
            System.Console.ReadKey();
        }