program uspon;
var a,b,c,d,e:integer;
arr:array[1..1000] of integer;
begin
readln(a);
for b:=1 to a do read(arr[b]);

c:=0;d:=0;
for b:=1 to a do begin
if arr[b+1]>arr[b] then c:=c+(arr[b+1]-arr[b]);
if arr[b+1]<=arr[b] then begin
if d<c then d:=c;
c:=0; end;
end;
writeln(d);
end.