child(zdravko, nikola).
child(zdravko, filip).
child(aleksandra, nikola).
child(aleksandra, filip).
parents(X, Y) :-
    child(Y, X).
children(X, Y, C) :-
    child(X, C),
    child(Y, C).
siblings(X, Y) :-
    parents(X, P1),
    parents(Y, P2),
    P1 == P2,
    X @> Y.

/*
teacher(hamna, intro_to_ai).
teacher(nikita, intro_to_ai).
teacher(dr_succi, networks).
teacher(nikita, networks).
likes(nikita, cofee).
likes(dr_succi, cofee).
likes(hamna, tea).
drives(dr_succi, car).
drives(hamna, car).
drives(nikita, bicycle).
pair(TA1, TA2) :-
    teacher(TA1, Course),
    teacher(TA2, Course),
    TA1 @> TA2.
pair(TA1, TA2) :-
    likes(TA1, X),
    likes(TA2, X),
    TA1 @> TA2.
pair(TA1, TA2) :-
    drives(TA1, X),
    drives(TA2, X),
    TA1 @> TA2.
*/