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.