a-a a-b a-c aaa aab aac aak aan aas aay ab- aba abb abc abk abn abs aby ac- aca acb acc ack acn acs acy aka akb akc akk akn aks an- ana anb anc ank ann ans any as- asa asb asc ask asn ass asy ay- aya ayc ayk ayn ays baa bab bac bak ban bas bay bba bbb bbc bbk bbn bbs bby bca bcb bcc bck bcn bcs bcy bka bkb bkc bkk bkn bks bna bnb bnc bnk bnn bns bsa bsb bsc bsk bsn bss bsy by- bya byc byk byn bys c-- caa cab cac cak can cas cay cba cbb cbc cbk cbn cbs cby cca ccb ccc cck ccn ccs cka ckb ckc cks cky cn- cna cnb cnc cnn cns cny csa csb csc csk csn css csy cya cyb cyc cyk cyn cys ka- kaa kab kac kak kan kas kay kba kbb kbc kbk kbn kbs kca kcb kcc kck kcn kcs kkb kkc kkk kkn kks kky kn- kna knc knk knn ksa ksb ksc ksk ksn kss kya kyc kyn kys naa nab nac nak nan nas nay nba nbb nbc nbk nbn nbs nca ncb ncc nck ncn ncs nka nkc nkk nkn nks nky nna nnb nnc nnk nnn nns nsa nsb nsc nsk nsn nss nsy nya nyc nyk nyn nys nyy saa sab sac sak san sas say sba sbb sbc sbk sbn sbs sby sca scb scc sck scn scs sk- ska skb skc skk sks sky sna snb snc snk snn sns sny ss- ssa ssb ssc ssk ssn sss sy- sya syb syc syk syn sys yaa yab yac yak yan yas yay ybc ybs yby yca ycc ycs ycy yka ykk ykn yna ynk ynn yns yny ysa ysb ysc ysk yss ysy yyb yyc yys yyy