static int loopy(int[] aa)
        {
            var min = aa.Min();
            var max = aa.Max();
            var expectedReps = max - min + 1; // <--- this is how many reps will be required

            int rep = 0;
            int i;
            HashSet<int> hash = new HashSet<int>();

            List<int> a = aa.Distinct().ToList();
            while (a.Count != 0)
            {
                foreach (int x in a)
                {
                    foreach (int y in a)
                    {
                        if (x != y) hash.Add(Math.Abs(x - y));
                    }
                }
                a = hash.ToList();
                hash.Clear();
                Console.WriteLine("a.Count = " + a.Count);
                /*
                for (i = 0; i < a.Count; ++i)
                {
                    Console.Write(" " + a[i]);
                }
                Console.WriteLine();*/
                ++rep;
            }
            if (rep == 0) rep = -1;

            Debug.Assert(expectedReps == rep); // hasn't failed on me yet

            return rep;
        }

        static async Task Main(string[] args)
        {
            while (true)
            {
                var r = new Random();
                var xs = new int[242];

                for (int i = 0; i < xs.Length; i++)
                {
                    xs[i] = r.Next(1, 1163);
                }

                loopy(xs);
            }
		}