:-dynamic(door/2).
:-consult('pr-intro2.pl').
door(a,b).
door(b,c).
door(b,d).
door(d,e).
door(x,y).
door(e,x).
has_phone(e).
has_phone(x).


%%go(X,Y) :- door(X,Y);door(X,Z),go(Z,Y).
go(X,Y) :- door(X,Y).
go(X,Y) :- door(X,Z),go(Z,Y).
%%go(X,Y) :- has_phone(X),has_phone(Y).
ok_at(X) :- go(X,Y),has_phone(Y).
happy(X) :- var(X),go(X,e).


myset([a,b,c]).
myset([]).
myset([1,2,3,4,5]).
myset(def).