procedure TForm1.Memo1Change(Sender: TObject);
var i:integer;
s:string;
begin
for i:=0 to memo1.Lines.Count do
  begin
  s:=memo1.Lines.Strings[i];
  if length(s)>70 then begin
  delete(s,71,length(s)-70);
  memo1.Lines.Strings[i]:=s;
  end;
  end;

end;