a-a a-b a-c a-t aaa aab aac aao aap aar aas aat ab- aba abb abc abo abp abr abs abt ac- aca acb acc aco acp acr acs act aoa aob aoc aoo aop aor aos aot ap- apa apb apc apo app apr aps apt ar- ara arb arc aro arp arr ars art as- asa asb asc aso asp asr ass ast at- ata atb atc ato atp atr ats att b-p baa bab bac bao bap bar bas bat bba bbb bbc bbo bbp bbr bbs bbt bca bcb bcc bco bcp bcr bcs bct boa bob boc boo bop bor bos bot bpa bpb bpc bpo bpp bpr bps bpt bra brb bro brp brr brs brt bsa bsb bsc bso bsp bsr bss bst bta btb btc bto btp btr bts btt c-- caa cab cac cao cap car cas cat cba cbb cbc cbo cbp cbr cbs cbt cca ccb ccc cco ccp ccr ccs cct co- coa cob coc coo cop cor cos cot cpa cpb cpc cpo cpp cpr cps cpt cra crb crc cro crp crr crs crt csa csb csc cso csp csr css cst cta ctb ctc cto ctp ctr cts ctt oaa oab oac oao oap oar oas oat ob- oba obb obc obo obp obr obs obt oc- oca ocb occ oco ocp ocr ocs oct oo- ooa oob ooc ooo oop oor oos oot op- opa opb opc opo opp opr ops opt or- ora orb orc oro orp orr ors ort os- osa osb osc oso osp osr oss ost ot- ota otb otc oto otp otr ots ott p-p paa pab pac pao pap par pas pat pba pbb pbc pbo pbp pbr pbs pbt pca pcb pcc pco pcp pcr pcs pct poa pob poc poo pop por pos pot ppa ppb ppc ppo ppp ppr pps ppt pra prb prc pro prp prr prs prt ps- psa psb psc pso psp psr pss pst pt- pta ptb ptc pto ptp ptr pts ptt ra- raa rab rac rao rap rar ras rat rba rbb rbc rbo rbp rbr rbs rbt rca rcb rcc rco rcp rcr rcs rct roa rob roc roo rop ror ros rot rpa rpb rpc rpo rpp rpr rps rpt rra rrb rrc rrp rrr rrs rrt rsa rsb rsc rso rsp rsr rss rst rta rtb rtc rto rtp rtr rts rtt saa sab sac sao sap sar sas sat sba sbb sbc sbo sbp sbr sbs sbt sca scb scc sco scp scr scs sct soa sob soc soo sop sor sos sot spa spb spc spo spp spr sps spt sr- sra srb src sro srp srr srs srt ss- ssa ssb ssc sso ssp ssr sss sst sta stb stc sto stp str sts stt taa tab tac tao tap tar tas tat tba tbb tbc tbo tbp tbr tbs tbt tca tcb tcc tco tcp tcr tcs tct to- toa tob toc too top tor tos tot tpa tpb tpc tpo tpp tpr tps tpt tra trb trc tro trp trr trs trt tsa tsb tsc tso tsp tsr tss tst tta ttb ttc tto ttp ttr tts ttt