program razine;
var i,n,min,s,max:longint;
a:array[1..5000] of longint;
begin
max:=0;
s:=0;
readln(n);
for i:=1 to n do
read(a[i]);
for i:=1 to n do begin
if a[i]<a[i+1] then s:=s+(a[i+1]-a[i]);

if a[i]>=a[i+1] then begin
if s>max  then max:=s;
s:=0;
end;



end;
writeln(max);

end.