public static void Test()
{
GoodTeacher s1 = new GoodTeacher();
Teacher s11 = s1 as Teacher;
OldTeacher <Student> s2 = new OldTeacher <Student>();
Teacher s22 = s2 as Teacher;
}
static void Main(string[] args)
{
Teacher teacher = new Teacher();
int money = 0;
teacher.EarnMoney(money);
GoodTeacher good_teacher = new GoodTeacher();
good_teacher.EarnMoney(money);
Console.ReadLine();
}
