a-a a-b a-c aaa aab aac aak aam aan ab- aba abb abc abk abm abn ac- aca acb acc ack acm acn aka akb akc akk akm akn ama amb amc amk amm amn an- ana anb anc ank anm ann baa bab bac bak bam ban bba bbb bbc bbk bbm bbn bca bcb bcc bck bcm bcn bka bkb bkc bkk bkm bkn bma bmb bmc bmk bmm bmn bna bnb bnc bnk bnn c-- caa cab cac cak cam can cba cbb cbc cbk cbm cbn cca ccb ccc cck ccm ccn cka ckb ckc ckm cma cmb cmc cmk cmm cmn cn- cna cnb cnc cnm cnn ka- kaa kab kac kak kam kan kba kbb kbc kbk kbm kbn kca kcb kcc kck kcm kcn kkb kkc kkk kkm kkn kma kmb kmc kmk kmm kn- kna knc knk knm knn maa mab mac mak mam man mba mbb mbc mbk mbm mc- mca mcb mcc mck mcm mcn mka mkb mkc mkk mkm mkn mma mmb mmc mmk mmm mmn mna mnb mnc mnk mnm mnn naa nab nac nak nam nan nba nbb nbc nbk nbm nbn nca ncb ncc nck ncm ncn nka nkc nkk nkm nkn nma nmb nmc nmk nmm nmn nna nnb nnc nnk nnm nnn