a-a a-b a-c aaa aab aac aak aap aar aas ab- aba abb abc abk abp abr abs ac- aca acb acc ack acp acr acs aka akb akc akk akp akr aks ap- apa apb apc apk app apr aps ar- ara arb arc ark arp arr ars as- asa asb asc ask asp asr ass b-p baa bab bac bak bap bar bas bba bbb bbc bbk bbp bbr bbs bca bcb bcc bck bcp bcr bcs bka bkb bkc bkk bkp bkr bks bpa bpb bpc bpp bpr bps bra brb brk brp brr brs bsa bsb bsc bsk bsp bsr bss c-- caa cab cac cak cap car cas cba cbb cbc cbk cbp cbr cbs cca ccb ccc cck ccp ccr ccs cka ckb ckc cks cpa cpb cpc cpk cpp cpr cps cra crb crc crk crp crr crs csa csb csc csk csp csr css ka- kaa kab kac kak kap kar kas kba kbb kbc kbk kbp kbr kbs kca kcb kcc kck kcp kcr kcs kkb kkc kkk kkp kkr kks kpa kpc kpk kpp kpr kps kra krc krk krp krr krs ksa ksb ksc ksk ksp ksr kss p-p paa pab pac pak pap par pas pba pbb pbc pbk pbp pbr pbs pca pcb pcc pck pcp pcr pcs pka pkb pkc pkp pkr pks ppa ppb ppc ppk ppp ppr pps pra prb prc prk prp prr prs ps- psa psb psc psk psp psr pss ra- raa rab rac rak rap rar ras rba rbb rbc rbk rbp rbr rbs rca rcb rcc rcp rcr rcs rkb rkc rkk rkp rks rpa rpb rpc rpk rpp rpr rps rra rrb rrc rrk rrp rrr rrs rsa rsb rsc rsk rsp rsr rss saa sab sac sak sap sar sas sba sbb sbc sbk sbp sbr sbs sca scb scc sck scp scr scs sk- ska skb skc skk skp skr sks spa spb spc spk spp spr sps sr- sra srb src srk srp srr srs ss- ssa ssb ssc ssk ssp ssr sss