a-a aaa aaf aak aao aap aar af- afa aff afk afo afp afr aka akk ako akp akr aoa aof aok aoo aop aor ap- apa apf apk apo app apr ar- ara arf ark aro arp arr faa faf fak fao fap far ffa fff ffk ffo ffp ffr fka fkf fkk fkp foa fof fok foo fop for fpa fpk fpo fpp fpr fra frf frk fro frp frr ka- kaa kaf kak kao kap kar kfa kff kfo kkk kkp kkr koa kof kok koo kop kor kpa kpf kpk kpo kpp kpr kra krf krk kro krp krr oaa oaf oak oao oap oar of- ofa off ofo ofp ofr oka okk oko okp okr oo- ooa oof ook ooo oop oor op- opa opf opk opo opp opr or- ora orf ork oro orp orr p-p paa paf pak pao pap par pfa pff pfk pfo pfp pfr pka pkf pko pkp pkr poa pof pok poo pop por ppa ppf ppk ppo ppp ppr pra prf prk pro prp prr ra- raa raf rak rao rap rar rfa rff rfk rfo rfp rfr rkf rkk rko rkp roa rof rok roo rop ror rpa rpf rpk rpo rpp rpr rra rrf rrk rrp rrr