i send this program:
var
  n,i:integer;
  bu:integer;
  a:array[1..15000]of integer;

begin
  readln(n);
  bu:=0;
  for i:=1 to n do begin
    readln(a[i]);
    while bu>=a[i] do bu:=bu;
    bu:=a[i];
  end;
  writeln('-1');
  readln;
end.

System must show TL if first list contains 0 or two equal numbers or not sorted.

But teacher's list may contain equal numbers. It's not error, I think.