Here is my code:

program Project2;

{$APPTYPE CONSOLE}

uses
  SysUtils;

var n,max,i,sum,a:integer;

begin
 max:=0;
 sum:=0;
 readln(n);
 for i:=1 to n do
  begin
   readln(a);
   sum:=sum+a;
   if sum>max then
    max:=sum;
  end;
 writeln(max);
end.

I've tested it. It is allright. But i get WA!!!
Why?

because you're trying to make set from i = 0 to all of j.
But answer may differ.