%2006c
pq(X):-member(Y,X),member(Z,X),not(member(A,Y),member(A,Z)),
write(Y),write(Z),write(A).
?-pq([[1,2],[2,4],[3,6]]).

sum([A],A).
sum([A|T],S):-sum(T,S1),S is S1 + 1.
second([A,B],B).
second([A,B|_],B).
q(X,Y):-not((member(A,X),sum(A,S),not((
								member(S,Y)
								))
		)).
pp(X,N):-member(Y,X),second(N,Y),q(X,Y).
%?-q([[1,2],[3,4]],[4,7]).

revert(X,Y).
suma([],0).
suma([B],B).
suma([B|T],X):-suma(T,X1),X is X1 + B.

f([A,B]):-suma(A,SA),suma(B,SB),SA*SB<0,write(SA),write(SB).
f([A,B|T]):-suma(A,SB),suma(B,SB),SA*SB<0,write(SA),write(SB),f(T).
f2([A,B]):-A<0,B>0.
f2([A,B|T]):-A<0,B>0,f2(T).

p09093(X).
p22(X,A):-member(B,X),member(A,B),
not(member(L,X),not(member(A,L),not(last(A,L)))).
last(A,[A]).
last(X,[H|T]):-last(X,T).

member(X,[X|_]).
member(X,[H|T]):-member(X,T).

ibasi(X,Y):-
member(B,X),
not(member(A,B),not(
not(
	member(L,X),not(
				  member(A,L),not(
							    last(A,L)
								)
					)
	)
,write(A))).

push2(X,[],[X]).
push2(X,[H|T],[H|L]):-push2(X,T,L).
e(0).
e(X):-e(Y),X is Y + 1, write(X),nl.

even(0).
even(X):-even(Y),X is Y + 2, write(X),nl.
%?-nmember(X,5,[1,2,3]),write(X).


nmember(A,1,[A|_]).
nmember(X,N,[H|T]):-N1 is N-1,nmember(X,N1,T).

len(0,[]).
len(1,[A]).
len(X,[H|T]):-len(X1,T),X is X1+1.

el([A,B]).
el([A,B|T]):-el(T).

same(X,Y):-member(A,X),member(A,Y).
podlist(X,Y):-not(member(A,X),not(member(A,Y))).

p1(L):-not(member(X,L),not(x<0)).
p2(L):-member(X,L),X<0.
p3(L):-not(member(X,L),not(member(Y,L),(X+Y)<0)).
p4(X,Y):-member(A,X),member(B,Y),member(A,B).
p5(X,Y):-member(A,X),not(member(B,Y),not(member(A,B))).
p6(X,Y):-not(member(A,X),not(member(B,Y),member(A,B))).
p7(X,Y):-not(member(A,X),member(B,Y),not(member(A,B))).
p8(X):-member(A,X),member(B,X),not(same(A,B)).
p9(X):-member(A,X),not(member(B,X),not(podlist(A,B))).
p10(X):-not(member(A,X),not(member(B,X),not(same(A,B)))).

p11(X,Y):-not(member(A,X),not(member(B,Y),member(A,B))).


push(X,[A],[A,X]).
push(X,[H|T],[H|Z]):-push(X,T,Z).

append([X|Y],Z,[X|W]) :- append(Y,Z,W).
append([],X,X).

between(A,A,B):-A=<B.
between(X,A,B):-A<B,A1 is A + 1,write(A), between(X,A1,B).
%?-between(X,1,5).
pitagor(X,Y,Z):-X*X+Y*Y=:=Z*Z.
%?-p09093([[1,2,3],[3,2,1],[3,2,2]]).
%?-f2([-5,1,-2,3,-3]).