a-a a-b a-t aaa aab aan aao aar aas aat ab- aba abb abn abo abr abs abt an- ana anb ann ano anr ans ant aoa aob aon aoo aor aos aot ar- ara arb arn aro arr ars art as- asa asb asn aso asr ass ast at- ata atb atn ato atr ats att baa bab ban bao bar bas bat bba bbb bbn bbo bbr bbs bbt bna bnb bnn bno bnr bns bnt boa bob bon boo bor bos bot bra brb brn bro brr brs brt bsa bsb bsn bso bsr bss bst bta btb btn bto btr bts btt naa nab nan nao nar nas nat nba nbb nbn nbo nbr nbs nbt nna nnb nnn nno nns nnt no- noa nob non noo nor nos not nra nrb nrn nro nrr nrs nrt nsa nsb nsn nso nsr nss nst nta ntb ntn nto ntr nts ntt oaa oab oan oao oar oas oat ob- oba obb obn obo obr obs obt on- ona onb onn ono onr ons ont oo- ooa oob oon ooo oor oos oot or- ora orb orn oro orr ors ort os- osa osb osn oso osr oss ost ot- ota otb otn oto otr ots ott ra- raa rab ran rao rar ras rat rba rbb rbn rbo rbr rbs rbt rna rnb rnn rno rnr rns rnt roa rob ron roo ror ros rot rra rrb rrn rrr rrs rrt rsa rsb rsn rso rsr rss rst rta rtb rtn rto rtr rts rtt saa sab san sao sar sas sat sba sbb sbn sbo sbr sbs sbt sna snb snn sno snr sns snt soa sob son soo sor sos sot sr- sra srb srn sro srr srs srt ss- ssa ssb ssn sso ssr sss sst sta stb stn sto str sts stt taa tab tan tao tar tas tat tba tbb tbn tbo tbr tbs tbt tna tnb tnn tno tnr tns tnt to- toa tob ton too tor tos tot tra trb trn tro trr trs trt tsa tsb tsn tso tsr tss tst tta ttb ttn tto ttr tts ttt