a-a a-b aaa aab aak aam aan aas ab- aba abb abk abm abn abs aka akb akk akm akn aks ama amb amk amm amn ams an- ana anb ank anm ann ans as- asa asb ask asm asn ass baa bab bak bam ban bas bba bbb bbk bbm bbn bbs bka bkb bkk bkm bkn bks bma bmb bmk bmm bmn bms bna bnb bnk bnn bns bsa bsb bsk bsm bsn bss ka- kaa kab kak kam kan kas kba kbb kbk kbm kbn kbs kkb kkk kkm kkn kks kma kmb kmk kmm kms kn- kna knk knm knn ksa ksb ksk ksm ksn kss maa mab mak mam man mas mba mbb mbk mbm mbs mka mkb mkk mkm mkn mks mma mmb mmk mmm mmn mms mna mnb mnk mnm mnn mns msa msb msk msm msn mss naa nab nak nam nan nas nba nbb nbk nbm nbn nbs nka nkk nkm nkn nks nma nmb nmk nmm nmn nms nna nnb nnk nnm nnn nns nsa nsb nsk nsm nsn nss saa sab sak sam san sas sba sbb sbk sbm sbn sbs sk- ska skb skk skm sks sma smb smk smm smn sms sna snb snk snm snn sns ss- ssa ssb ssk ssm ssn sss