a-a aaa aaf aak aao aap aar aas af- afa aff afk afo afp afr afs aka akk ako akp akr aks aoa aof aok aoo aop aor aos ap- apa apf apk apo app apr aps ar- ara arf ark aro arp arr ars as- asa asf ask aso asp asr ass faa faf fak fao fap far fas ffa fff ffk ffo ffp ffr ffs fka fkf fkk fkp foa fof fok foo fop for fos fpa fpk fpo fpp fpr fps fra frf frk fro frp frr frs fsa fsf fsk fso fsp fsr fss ka- kaa kaf kak kao kap kar kas kfa kff kfo kfs kkk kkp kkr kks koa kof kok koo kop kor kos kpa kpf kpk kpo kpp kpr kps kra krf krk kro krp krr krs ksa ksf ksk kso ksp ksr kss oaa oaf oak oao oap oar oas of- ofa off ofo ofp ofr ofs oka okk oko okp okr oks oo- ooa oof ook ooo oop oor oos op- opa opf opk opo opp opr ops or- ora orf ork oro orp orr ors os- osa osf osk oso osp osr oss p-p paa paf pak pao pap par pas pfa pff pfk pfo pfp pfr pfs pka pkf pko pkp pkr pks poa pof pok poo pop por pos ppa ppf ppk ppo ppp ppr pps pra prf prk pro prp prr prs ps- psa psf psk pso psp psr pss ra- raa raf rak rao rap rar ras rfa rff rfk rfo rfp rfr rfs rkf rkk rko rkp rks roa rof rok roo rop ror ros rpa rpf rpk rpo rpp rpr rps rra rrf rrk rrp rrr rrs rsa rsf rsk rso rsp rsr rss saa saf sak sao sap sar sas sfa sff sfk sfo sfp sfr sfs sk- ska skf skk sko skp skr sks soa sof sok soo sop sor sos spa spf spk spo spp spr sps sr- sra srf srk sro srp srr srs ss- ssa ssf ssk sso ssp ssr sss