public override void IntroduceYourself(Person person)
 {
     if (person.IsHungry() == false)
     {
         Console.WriteLine(person.ToString() + "\nI am not hungry!");
     }
     else
     {
         Console.WriteLine(person.ToString() + "\nI am hungry!");
     }
 }
 public abstract void IntroduceYourself(Person person);