male(jahir).
male(joual).
male(joy).
male(roni).
male(zayan).
female(rahela).
female(ruma).
female(monni).
female(faiza).
female(kashpia).
female(takia).

parent(jahir, joual).
parent(jahir, joy).
parent(jahir, monni).
parent(rahela, joual).
parent(rahela, joy).
parent(rahela, monni).
parent(roni, kashpia).
parent(roni, takia).
parent(monni, kashpia).
parent(monni, takia).
parent(ruma, faiza).
parent(ruma, zayan).
parent(joual, faiza).
parent(joual, zayan).

father_of(X, Y) :- parent(X, Y), male(X).
mother_of(X, Y) :- parent(X, Y), female(X).
brother_of(X, Y) :- father_of(A, X), father_of(A, Y), male(X), X \= Y.
sister_of(X, Y) :- father_of(A, X), father_of(A, Y), female(X), X \= Y.
grandfather_of(X, Y) :- parent(X, Z), parent(Z, Y), male(X).
grandmother_of(X, Y) :- parent(X, Z), parent(Z, Y), female(X).