var
     min,max,t,z,v:Integer;
     a,b: string;
begin
  a := '';
  b := '';
  Listbox1.Items.Clear;
  min := strtoint(edit1.Text);
  max := strtoint(edit2.Text)+1;
  for z := min to max do
  begin
    t := 2;
    while (z mod t <> 0) AND (t < z) do t := t+1;
    if z = t then
    begin
      if a = '' then a := inttostr(z) else
      if b = '' then b := inttostr(z) else
      begin
        v := strtoint(b);
        if strtoint(a)+2 = strtoint(b) then listbox1.Items.Add(a+' - '+b);
        a := inttostr(z);
        if v+2 = strtoint(a) then  listbox1.Items.Add(inttostr(v)+' - '+a);
        b := '';
      end;
    end;
  end;
end;