public void HackerRankTest()
        {
            int result = UtopianTree.HeightAt(5);

            Assert.That(result, Is.EqualTo(14));
        }
        public void HackerRankOther4Test()
        {
            int result = UtopianTree.HeightAt(4);

            Assert.That(result, Is.EqualTo(7));
        }