A marca de deux

INTRO:

      1-5-5-5--3-1-0---10-10-10--8-6-5-3--9-9-9--9-10-9-12----------------------+
      2--------------3-------------------------------------10--10-10-10-8-6-5---+
      3-----------------------------------------------------------------------7-+
      4-------------------------------------------------------------------------+
      5-------------------------------------------------------------------------+
      6-------------------------------------------------------------------------+