:- discontiguous male/1, female/1, parent/2.
male(dicky).
male(randy).
male(mike).
male(don).
male(elmer).
female(anne).
female(rosie).
female(esther).
female(mildred).
female(greatgramma).
male(blair).

parent(don,randy).
parent(don,mike).
parent(don,anne).
parent(rosie,randy).
parent(rosie,mike).
parent(rosie,anne).
parent(elmer,don).
parent(mildred,don).
parent(esther,rosie).
parent(esther,dicky).
parent(greatgramma,esther).
parent(randy,blair).
parent(mike,juliet).

male(mel).
male(teo).
parent(melsr,mel).
parent(melsr,teo).

father(X,Y) :- male(X),parent(X,Y).
mother(X,Y) :- female(X),parent(X,Y).
son(X,Y) :- male(X),parent(Y,X).
dauther(X,Y) :- female(X),parent(Y,X).
uncle(X,Y) :- male(X),brother(X,Z),parent(Z,Y).
aunt(X,Y) :- female(X),sister(X,Z),parent(Z,Y).

grandmother(X,Y) :- mother(Z,Y),mother(X,Z).
grandmother(X,Y) :- father(Z,Y),mother(X,Z).

grandmother(X,Y) :- female(X),parent(Z,Y),parent(X,Z).

%grandfather
sister(X,Y) :- female(X),parent(Z,X),parent(Z,Y),X\=Y.
brother(X,Y) :- male(X),parent(Z,X),parent(Z,Y),X\=Y.
cousin(X,Y) :- uncle(Z,Y),parent(Z,X).
cousin(X,Y) :- aunt(Z,Y),parent(Z,X).

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