uncle(Uncle,Person) :-
		brother(Uncle,Parent), parent(Parent,Person).

	sibling(Sib1,Sib2) :-
		parent(Parent,Sib1), parent(Parent,SIb2), Sib1 \= Sib2.

	cousin(Cousin1,Cousin2) :-
		parent(Parent1,Cousin1),
		parent(Parent2,Cousin2),
		sibling(Parent1,Parent2).

%	Program 2.1:  Defining family relationships