?-sortin([9,3,2 6,1,13],R,<).
		R = [1,2,3,6,9,13]

		?-sortin([9,3,2,6,1,13],R,>).
		R = [13,9,6,3,2,1]

		inser(A,[],[A],P).
		inser(A,[H|L],R,P):- P(A,H),append([A,H],L,R),!.
		inser(A,[H|L],[H|R],P):- inser(A,L,R,P).

		sortin([],[],P).
		sortin([H|L],Re,P):- sortin(L,R,P),inser(H,R,Re,P).