a-a a-b aaa aab aah aak aan aao aar ab- aba abb abh abk abn abo abr aha ahb ahh ahk ahn aho ahr aka akb akh akk akn ako akr an- ana anb anh ank ann ano anr aoa aob aoh aok aon aoo aor ar- ara arb arh ark arn aro arr baa bab bah bak ban bao bar bba bbb bbh bbk bbn bbo bbr bha bhb bhh bhk bho bhr bka bkb bkk bkn bko bkr bna bnb bnk bnn bno bnr boa bob boh bok bon boo bor bra brb brh brk brn bro brr haa hab hah hak han hao har hba hbb hbh hbk hbn hbo hbr hha hhb hhh hhk hhn hho hhr hka hkb hkh hkk hkn hko hkr hna hnb hnh hnk hnn hno hoa hob hoh hok hon hoo hor hr- hra hrb hrh hrk hrn hro hrr ka- kaa kab kah kak kan kao kar kba kbb kbh kbk kbn kbo kbr kha khh khk khn kho khr kkb kkh kkk kkn kkr kn- kna knk knn kno knr koa kob koh kok kon koo kor kra krk krn kro krr naa nab nah nak nan nao nar nba nbb nbk nbn nbo nbr nha nhb nhh nhk nhn nhr nka nkk nkn nko nkr nna nnb nnh nnk nnn nno no- noa nob noh nok non noo nor nra nrb nrk nrn nro nrr oaa oab oah oak oan oao oar ob- oba obb obh obk obn obo obr oha ohh ohn oho ohr oka okb okk oko okr on- ona onb onh onk onn ono onr oo- ooa oob ooh ook oon ooo oor or- ora orb orh ork orn oro orr ra- raa rab rah rak ran rao rar rba rbb rbh rbk rbn rbo rbr rh- rha rhb rhh rhn rho rhr rkb rkk rko rna rnb rnh rnn rno rnr roa rob roh rok ron roo ror rra rrb rrh rrk rrn rrr