procedure TForm1.Button1Click(Sender: TObject);
var n,i,j,sum:integer;a:array[1..20,1..20] of integer;
begin
n:=strtoint(Edit1.Text);
randomize;
for i:=1 to n do
for j:=1 to n do
a[i,j]:=random(10)-4;
for i:=1 to n do
for j:=1 to n do
     begin
       StringGrid1.Cells[j-1,i-1]:=inttostr(a[i,j]);
     end;
sum:=0;
for i:=2 to n do
for j:=n-i+2 to n do
  if a[i,j]<0 then
     begin
      sum:=sum+a[i,j];
     end;
Edit2.Text:=inttostr(sum);
   end;
end.