public void Test2()
        {
            int[] a = new int[] { 1, 2, 3, 4, 5, 6, 7, 2, 3, 5, 6, 1, 4 };

            Assert.AreEqual(7, Unpaired.Solve(a));
        }
        public void Test1()
        {
            int[] a = new int[] { 2, 2, 3, 3, 4, 4, 5 };

            Assert.AreEqual(5, Unpaired.Solve(a));
        }