public void TestMethod2()
        {
            //Arrange
            int  n        = 1000;
            long expected = 1366;

            //Act
            var res = PowerDigitSum.Solve(n);

            //Assert
            Assert.AreEqual(expected, res);
        }
        public void TestMethod1()
        {
            //Arrange
            var n        = 15;
            var expected = 26;

            //Act
            var res = PowerDigitSum.Solve(15);

            //Assert
            Assert.AreEqual(expected, res);
        }