a-a a-b a-t aaa aab aak aar aas aat ab- aba abb abk abr abs abt aka akb akk akr aks ar- ara arb ark arr ars art as- asa asb ask asr ass ast at- ata atb atr ats att baa bab bak bar bas bat bba bbb bbk bbr bbs bbt bka bkb bkk bkr bks bkt bra brb brk brr brs brt bsa bsb bsk bsr bss bst bta btb btk btr bts btt k-t ka- kaa kab kak kar kas kat kba kbb kbk kbr kbs kkb kkk kkr kks kkt kra krk krr krs krt ksa ksb ksk ksr kss kst kta ktb ktk ktr kts ktt ra- raa rab rak rar ras rat rba rbb rbk rbr rbs rbt rkb rkk rks rkt rra rrb rrk rrr rrs rrt rsa rsb rsk rsr rss rst rta rtb rtk rtr rts rtt saa sab sak sar sas sat sba sbb sbk sbr sbs sbt sk- ska skb skk skr sks skt sr- sra srb srk srr srs srt ss- ssa ssb ssk ssr sss sst sta stb stk str sts stt taa tab tak tar tas tat tba tbb tbk tbr tbs tbt tka tkb tkk tkr tks tkt tra trb trk trr trs trt tsa tsb tsk tsr tss tst tta ttb ttk ttr tts ttt