-er a-a a-b aaa aab aad aae aak aar aas ab- aba abb abd abe abk abr abs ad- ada adb add ade adk adr ads aea aeb aed aee aek aer aes aka akb akd ake akk akr aks ar- ara arb ard are ark arr ars as- asa asb asd ase ask asr ass baa bab bad bae bak bar bas bba bbb bbd bbe bbk bbr bbs bda bdb bdd bde bdk bdr bds be- bea beb bed bee bek ber bes bka bkb bke bkk bkr bks bra brb brd bre brk brr brs bsa bsb bsd bse bsk bsr bss daa dab dad dae dak dar das dba dbb dbd dbe dbk dbr dbs dda ddb ddd dde ddk ddr dds de- dea deb ded dee dek der des dka dkb dke dkk dkr dks dra drb drd dre drk drr drs dsa dsb dsd dse dsk dsr dss eaa eab ead eae eak ear eas eba ebb ebd ebe ebk ebr ebs ed- eda edb edd ede edk edr eds eea eeb eed eee eek eer ees eka ekb ekd eke ekr eks era erb erd ere erk err ers es- esa esb esd ese esk esr ess ka- kaa kab kad kae kak kar kas kba kbb kbd kbe kbk kbr kbs kda kdb kde kdk kdr kds ke- kea keb ked kee kek ker kes kkb kke kkk kkr kks kra krd krk krr krs ksa ksb ksd kse ksk ksr kss ra- raa rab rad rae rak rar ras rba rbb rbd rbe rbk rbr rbs rda rdb rdd rde rdr rds re- rea reb red ree rek rer res rkb rke rkk rks rra rrb rrd rrk rrr rrs rsa rsb rsd rse rsk rsr rss saa sab sad sae sak sar sas sba sbb sbd sbe sbk sbr sbs sda sdb sdd sde sdk sdr sds se- sea seb sed see sek ser ses sk- ska skb skd ske skk skr sks sr- sra srb srd sre srk srr srs ss- ssa ssb ssd sse ssk ssr sss