a-a a-b a-t aaa aab aak aao aap aar aat ab- aba abb abk abo abp abr abt aka akb akk ako akp akr aoa aob aok aoo aop aor aot ap- apa apb apk apo app apr apt ar- ara arb ark aro arp arr art at- ata atb ato atp atr att b-p baa bab bak bao bap bar bat bba bbb bbk bbo bbp bbr bbt bka bkb bkk bko bkp bkr bkt boa bob bok boo bop bor bot bpa bpb bpo bpp bpr bpt bra brb brk bro brp brr brt bta btb btk bto btp btr btt k-t ka- kaa kab kak kao kap kar kat kba kbb kbk kbo kbp kbr kkb kkk kkp kkr kkt koa kob kok koo kop kor kot kpa kpk kpo kpp kpr kpt kra krk kro krp krr krt kta ktb ktk kto ktp ktr ktt oaa oab oak oao oap oar oat ob- oba obb obk obo obp obr obt oka okb okk oko okp okr oo- ooa oob ook ooo oop oor oot op- opa opb opk opo opp opr opt or- ora orb ork oro orp orr ort ot- ota otb otk oto otp otr ott p-p paa pab pak pao pap par pat pba pbb pbk pbo pbp pbr pbt pka pkb pko pkp pkr pkt poa pob pok poo pop por pot ppa ppb ppk ppo ppp ppr ppt pra prb prk pro prp prr prt pt- pta ptb ptk pto ptp ptr ptt ra- raa rab rak rao rap rar rat rba rbb rbk rbo rbp rbr rbt rkb rkk rko rkp rkt roa rob rok roo rop ror rot rpa rpb rpk rpo rpp rpr rpt rra rrb rrk rrp rrr rrt rta rtb rtk rto rtp rtr rtt taa tab tak tao tap tar tat tba tbb tbk tbo tbp tbr tbt tka tkb tkk tko tkp tkr tkt to- toa tob tok too top tor tot tpa tpb tpk tpo tpp tpr tpt tra trb trk tro trp trr trt tta ttb ttk tto ttp ttr ttt