door(g,h).
door(a,b).
door(b,c).
door(b,d).
door(d,f).
door(f,e).
hasphone(e).
hasphone(f).

%%=============

go(X,X,_).
go(X,Y,T):-(door(X,Z);door(Z,X)), not(member(Z,T)), go(Z,Y,[Z|T]).

findphone(S,E):-go(S,E,[]),hasphone(E).

%%============

go(X,X,P,P).
go(X,Y,T,P):-(door(X,Z);door(Z,X)), not( member(Z,T)), go(Z,Y,[Z|T],P).
findphone(S,E,P):-go(S,E,[],Px),hasphone(E),reverse(P,Px).

%%====================



move(1).
move(2).
move(3).
move(4).

win(N,M):-move(M), Nx is N-M, (Nx=<0 ; not(win(Nx,_))).