a-a a-b aaa aab aak aap aar aas ab- aba abb abk abp abr abs aka akb akk akp akr aks ap- apa apb apk app apr aps ar- ara arb ark arp arr ars as- asa asb ask asp asr ass b-p baa bab bak bap bar bas bba bbb bbk bbp bbr bbs bka bkb bkk bkp bkr bks bpa bpb bpp bpr bps bra brb brk brp brr brs bsa bsb bsk bsp bsr bss ka- kaa kab kak kap kar kas kba kbb kbk kbp kbr kbs kkb kkk kkp kkr kks kpa kpk kpp kpr kps kra krk krp krr krs ksa ksb ksk ksp ksr kss p-p paa pab pak pap par pas pba pbb pbk pbp pbr pbs pka pkb pkp pkr pks ppa ppb ppk ppp ppr pps pra prb prk prp prr prs ps- psa psb psk psp psr pss ra- raa rab rak rap rar ras rba rbb rbk rbp rbr rbs rkb rkk rkp rks rpa rpb rpk rpp rpr rps rra rrb rrk rrp rrr rrs rsa rsb rsk rsp rsr rss saa sab sak sap sar sas sba sbb sbk sbp sbr sbs sk- ska skb skk skp skr sks spa spb spk spp spr sps sr- sra srb srk srp srr srs ss- ssa ssb ssk ssp ssr sss