a-a aaa aaf aak aan aao aar af- afa aff afk afn afo afr aka akk akn ako akr an- ana anf ank ann ano anr aoa aof aok aon aoo aor ar- ara arf ark arn aro arr faa faf fak fan fao far ffa fff ffk ffn ffo ffr fka fkf fkk fna fnf fnk fnn fnr foa fof fok fon foo for fra frf frk frn fro frr ka- kaa kaf kak kan kao kar kfa kff kfo kkk kkn kkr kn- kna knf knk knn kno knr koa kof kok kon koo kor kra krf krk krn kro krr naa naf nak nan nao nar nfa nff nfk nfn nfo nfr nka nkf nkk nkn nko nkr nna nnf nnk nnn nno no- noa nof nok non noo nor nra nrf nrk nrn nro nrr oaa oaf oak oan oao oar of- ofa off ofn ofo ofr oka okk oko okr on- ona onf onk onn ono onr oo- ooa oof ook oon ooo oor or- ora orf ork orn oro orr ra- raa raf rak ran rao rar rfa rff rfk rfn rfo rfr rkf rkk rko rna rnn rno rnr roa rof rok ron roo ror rra rrf rrk rrn rrr