domains
	int=integer
	list=integer*
predicates
	merge1(list,list,list,list)
	merge(list,list,list)
	trans(list,list)
	member(int,list)
clauses
	merge1(A,B,C,D):-merge(A,B,C),trans(C,D).
	merge([],X2,X2):-!.
	merge(X1,[],X1):-!.
	merge([H1|T1],[H2|T2],[H1|T3]):-H1<=H2,!,
			    merge(T1,[H2|T2],T3).
	merge([H1|T1],[H2|T2],[H2|T3]):-
			    merge([H1|T1],T2,T3).
	trans([],[]).
	trans([X|L],S):-member(X,L),!,trans(L,S).
	trans([X|L],[X|S]):-trans(L,S).
	member(X,[X|_]).
	member(X,[_|Y]):-member(X,Y).
goal
	merge1([1,2,4,6,7,8],[2,4,6,8,9,10],M,N),
	write(N).