a-a a-b a-t aaa aab aak aao aar aat aay ab- aba abb abk abo abr abt aby aka akb akk ako akr aoa aob aok aoo aor aot ar- ara arb ark aro arr art ary at- ata atb ato atr att ay- aya ayk ayo ayr ayt baa bab bak bao bar bat bay bba bbb bbk bbo bbr bbt bby bka bkb bkk bko bkr bkt boa bob bok boo bor bot boy bra brb brk bro brr brt bry bta btb btk bto btr btt bty by- bya byk byo byr byt k-t ka- kaa kab kak kao kar kat kay kba kbb kbk kbo kbr kkb kkk kkr kkt kky koa kob kok koo kor kot koy kra krk kro krr krt kry kta ktb ktk kto ktr ktt kya kyo kyr kyt oaa oab oak oao oar oat ob- oba obb obk obo obr obt oby oka okb okk oko okr oo- ooa oob ook ooo oor oot or- ora orb ork oro orr ort ory ot- ota otb otk oto otr ott oya oyo ra- raa rab rak rao rar rat ray rba rbb rbk rbo rbr rbt rkb rkk rko rkt rky roa rob rok roo ror rot roy rra rrb rrk rrr rrt rta rtb rtk rto rtr rtt rty ry- rya ryk ryo ryr ryy taa tab tak tao tar tat tay tba tbb tbk tbo tbr tbt tka tkb tkk tko tkr tkt tky to- toa tob tok too tor tot toy tra trb trk tro trr trt try tta ttb ttk tto ttr ttt tty tya tyo tyr tyt yaa yab yak yao yar yat yay ybr yby yka ykk yob yok yoo yor yot yoy yra yro yrt yta ytk yto ytr ytt yyb yyt yyy