person(bethbeth).
person(james).
person(pam).
person(earl).
person(dv).

parent(bethbeth,dv).
parent(earl,dv).
parent(james,earl).
parent(pam,earl).

basicgrandparent(X,Y):-
	parent(X,Z),
	parent(Z,Y).

goodishgrandparent(X,Y):-
	parent(Z,Y),
	parent(X,Z),!.

badgrandparent(X,Y):-
	parent(Z,Y),!,
	parent(X,Z).

alsobad(X,Y):-
	parent(X,Z),!,
	parent(Z,Y).