a-a a-b a-c aaa aab aac aak aam aan aar ab- aba abb abc abk abm abn abr ac- aca acb acc ack acm acn acr aka akb akc akk akm akn akr ama amb amc amk amm amn amr an- ana anb anc ank anm ann anr ar- ara arb arc ark arm arn arr baa bab bac bak bam ban bar bba bbb bbc bbk bbm bbn bbr bca bcb bcc bck bcm bcn bcr bka bkb bkc bkk bkm bkn bkr bma bmb bmc bmk bmm bmn bmr bna bnb bnc bnk bnn bnr bra brb brk brm brn brr c-- caa cab cac cak cam can car cba cbb cbc cbk cbm cbn cbr cca ccb ccc cck ccm ccn ccr cka ckb ckc ckm cma cmb cmc cmk cmm cmn cmr cn- cna cnb cnc cnm cnn cnr cra crb crc crk crm crn crr ka- kaa kab kac kak kam kan kar kba kbb kbc kbk kbm kbn kbr kca kcb kcc kck kcm kcn kcr kkb kkc kkk kkm kkn kkr kma kmb kmc kmk kmm kn- kna knc knk knm knn knr kra krc krk krn krr m-r maa mab mac mak mam man mar mba mbb mbc mbk mbm mbr mc- mca mcb mcc mck mcm mcn mcr mka mkb mkc mkk mkm mkn mkr mma mmb mmc mmk mmm mmn mmr mna mnb mnc mnk mnm mnn mnr mra mrb mrc mrk mrm mrn mrr naa nab nac nak nam nan nar nba nbb nbc nbk nbm nbn nbr nca ncb ncc nck ncm ncn ncr nka nkc nkk nkm nkn nkr nma nmb nmc nmk nmm nmn nmr nna nnb nnc nnk nnm nnn nra nrb nrc nrk nrm nrn nrr ra- raa rab rac rak ram ran rar rba rbb rbc rbk rbm rbn rbr rca rcb rcc rcm rcn rcr rkb rkc rkk rkm rma rmb rmc rmm rmn rmr rna rnb rnc rnm rnn rnr rra rrb rrc rrk rrm rrn rrr