static void Main(string[] args)
{
Instructor john = new Instructor("John", "", "English");
Instructor mike = new Instructor("Mike", "", "Math");
Student jane = new Student("Jane", john);
Student joe = new Student("Joe", john);
Student melissa = new Student("Melissa", mike);
Student matt = new Student("Matt", mike);
john.SetStudntGrade(jane, 95);
john.SetStudntGrade(joe, 85);
mike.SetStudntGrade(melissa, 90);
mike.SetStudntGrade(matt, 92);
jane.Print();
joe.Print();
melissa.Print();
matt.Print();
System.Console.WriteLine("Press any key to exit");
System.Console.Read();
}