static void Main(string[] args)
{
Employee dev1 = new Developer("Kiran");
Employee dev2 = new Developer("Bhaskar");
Employee manager = new Manager("Vaibhav");
manager.AddEmployee(dev1);
manager.AddEmployee(dev2);
Employee director1 = new Director("Brian");
director1.AddEmployee(manager);
dev1 = new Developer("Viswa");
dev2 = new Developer("Anil");
manager = new Manager("Narasimha");
manager.AddEmployee(dev1);
manager.AddEmployee(dev2);
Director director2 = new Director("Mike");
director2.AddEmployee(manager);
Employee ceo = new CEO();
ceo.AddEmployee(director1);
ceo.AddEmployee(director2);
ceo.PerformanceReview();
}