import java.util.*;
class Person {
	String name;
	int born;
	Person father,mother;
	List children;

	Person(String name, int born, Person father, Person mother){
		this.name = name;
		this.born = born;
		this.father = father;
		this.mother = mother;
		children = new ArrayList();
		father.addChild( this );
		mother.addChild( this );
	}

	void addChild(Person p){
		// pre: p has this as mother or father;
		children.add(p);
	}

	int offspring(){
		int res = children.size();
		for (int i=0;i<children.size();i++)
			res += ( (Person)children.get( i ) ).offspring();
		return res;
	}

	private Set siblings(){
		Set s = new HashSet();
		s.addAll( father.children );
		s.addAll( mother.children );
		s.remove(this);
		return s;
	}


	List unclesAndAunts(){
		List res = new ArrayList();
		res.addAll( father.siblings() );
		res.addAll( mother.siblings() );
		return res;
	}

}