program anchovies;
Uses Math;
var N, i, prezzominimo, prezzoacquisto, maxprofitto : Longint;
    P : array[1..100000] of  Longint;
 
begin
	readln(N);
	for i:=1 to N do readln(P[i]);
	prezzominimo:=P[1];
	maxprofitto:=0;
	for i:=2 to N do 
	               begin
	                  if P[i]<prezzominimo then prezzominimo:= P[i]
	                                       else
	                                          if P[i]>prezzominimo then
	                                              begin
	                                                 prezzoacquisto:=prezzominimo;
	                                                 maxprofitto:=max(maxprofitto, P[i]-prezzoacquisto);
	                                              end;
	               end;
  writeln(maxprofitto);	               
end.

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