procedure TForm1.Button1Click(Sender: TObject);
var
  I: Integer;
begin
  sgFloor.RowCount := adotSeats['Rows'] + 1;
  sgFloor.ColCount := adotSeats['Seats_per_Row'] + 1;

  for I := 1 to sgFloor.ColCount - 1 do
    sgFloor.Cells[I, 0] := IntToStr(I);
  for I := 1 to sgFloor.RowCount - 1 do
    sgFloor.Cells[0, I] := Chr(64 + I);
end;