bbbb bbdd bbrc bcbc bccc bd-r bdbc bddc bnrr brcb brrr c-cd cbbc cbcc cbcn cbcr cbdb cbdc cbdn cbnd cbrd cbrn ccbc ccbn cccb cccc ccdc ccdn ccdr ccnb ccnc ccnr ccrc cd-r cddb cddr cdnb cdnc cnbc cndd cnrc cnrr crbc crcc crcr crdc dbcc dbrn dcbc dccb dccc dcdb dddd ddrc dnrc drbc nbbc nbcc ncbc nccc nccn nccr ncdc ncdn ncdr ncnc ncnd ncrc ndcc nddb ndrc nndb nnnn nrdc nrrc nrrd rbbb rbbr rcbc rccb rccc rcdc rcnr rcrd rnbr rndc rrrr