procedure TFormCalc.GiveAButtonTextToCount(AButtonText: string; ACountNumberElement: integer);
begin
   if (CountElements[ACountNumberElement].Text = '') or (CountElements[ACountNumberElement].Text = '0') then
      CountElements[ACountNumberElement].Text:= AButtonText
   else
   begin
     CountElements[ACountNumberElement].Text += AButtonText;
   end;
   FillLabelResult();
end;