public void Diff21Test_n30_return18()
 {
     Assert.AreEqual(18, Diff21.ShowAnswer(30));
 }
 public void Diff21Test_n10_return11()
 {
     Assert.AreEqual(8, Diff21.ShowAnswer(25));
 }
 public void Diff21Test_n21_return0()
 {
     Assert.AreEqual(0, Diff21.ShowAnswer(21));
 }
 public void Diff21Test_n19_return2()
 {
     Assert.AreEqual(2, Diff21.ShowAnswer(19));
 }