/*
   maxlist(Xs,N) :- N is the maximum of the list of integers Xs.
*/
     maxlist([X|Xs],M) :- maxlist(Xs,X,M).

     maxlist([X|Xs],Y,M) :- maximum(X,Y,Y1), maxlist(Xs,Y1,M).
     maxlist([],M,M).

	maximum(X,Y,Y) :- X =< Y.
	maximum(X,Y,X) :- X > Y.

%  Program 8.9    Finding the maximum of a list of integers