-er a-a a-b aaa aab aae aak aap aar aas ab- aba abb abe abk abp abr abs aea aeb aee aek aep aer aes aka akb ake akk akp akr aks ap- apa apb ape apk app apr aps ar- ara arb are ark arp arr ars as- asa asb ase ask asp asr ass b-p baa bab bae bak bap bar bas bba bbb bbe bbk bbp bbr bbs be- bea beb bee bek bep ber bes bka bkb bke bkk bkp bkr bks bpa bpb bpe bpp bpr bps bra brb bre brk brp brr brs bsa bsb bse bsk bsp bsr bss eaa eab eae eak eap ear eas eba ebb ebe ebk ebp ebr ebs eea eeb eee eek eep eer ees eka ekb eke ekp ekr eks ep- epa epb epe epp epr eps era erb ere erk erp err ers es- esa esb ese esk esp esr ess ka- kaa kab kae kak kap kar kas kba kbb kbe kbk kbp kbr kbs ke- kea keb kee kek kep ker kes kkb kke kkk kkp kkr kks kpa kpe kpk kpp kpr kps kra krk krp krr krs ksa ksb kse ksk ksp ksr kss p-p paa pab pae pak pap par pas pba pbb pbe pbk pbp pbr pbs pea peb pee pek pep per pes pka pkb pke pkp pkr pks ppa ppb ppe ppk ppp ppr pps pra prb pre prk prp prr prs ps- psa psb pse psk psp psr pss ra- raa rab rae rak rap rar ras rba rbb rbe rbk rbp rbr rbs re- rea reb ree rek rep rer res rkb rke rkk rkp rks rpa rpb rpe rpk rpp rpr rps rra rrb rrk rrp rrr rrs rsa rsb rse rsk rsp rsr rss saa sab sae sak sap sar sas sba sbb sbe sbk sbp sbr sbs se- sea seb see sek sep ser ses sk- ska skb ske skk skp skr sks spa spb spe spk spp spr sps sr- sra srb sre srk srp srr srs ss- ssa ssb sse ssk ssp ssr sss