-er a-a a-b a-c aaa aab aac aae aaf aak aam aao aar ab- aba abb abc abe abf abk abm abo abr ac- aca acb acc ace acf ack acm aco acr aea aeb aec aee aef aek aem aeo aer af- afa afb afc afe aff afk afm afo afr aka akb akc ake akk akm ako akr ama amb amc ame amf amk amm amo amr aoa aob aoc aoe aof aok aom aoo aor ar- ara arb arc are arf ark arm aro arr baa bab bac bae baf bak bam bao bar bba bbb bbc bbe bbf bbk bbm bbo bbr bca bcb bcc bce bcf bck bcm bco bcr be- bea beb bec bee bef bek bem beo ber bfa bfb bfc bfe bff bfm bfo bfr bka bkb bkc bke bkf bkk bkm bko bkr bma bmb bmc bme bmf bmk bmm bmo bmr boa bob boc boe bof bok bom boo bor bra brb bre brf brk brm bro brr c-- caa cab cac cae caf cak cam cao car cba cbb cbc cbe cbf cbk cbm cbo cbr cca ccb ccc cce ccf cck ccm cco ccr ce- cea ceb cec cee cef cek cem ceo cer cfa cfb cfc cfe cff cfk cfm cfo cfr cka ckb ckc ckm cko cma cmb cmc cme cmf cmk cmm cmo cmr co- coa cob coc coe cof cok com coo cor cra crb crc cre crf crk crm cro crr eaa eab eac eae eaf eak eam eao ear eba ebb ebc ebe ebf ebk ebm ebo ebr ec- eca ecb ecc ece ecf eck ecm eco ecr eea eeb eec eee eef eek eem eeo eer ef- efa efb efc efe eff efm efo efr eka ekb ekc eke ekf eko ekr em- ema emb emc eme emf emk emm emo emr eo- eoa eob eoc eoe eof eok eom eoo eor era erb erc ere erf erk erm ero err faa fab fac fae faf fak fam fao far fba fbb fbc fbe fbf fbk fbm fbo fbr fca fcb fcc fce fcf fck fcm fco fcr fea feb fec fee fef fek fem feo fer ffa ffc ffe fff ffk ffm ffo ffr fka fkb fkc fkf fkk fkm fma fmb fmc fme fmf fmm fmo fmr foa fob foc foe fof fok fom foo for fra frb frc fre frf frk frm fro frr ka- kaa kab kac kae kaf kak kam kao kar kba kbb kbc kbe kbf kbk kbm kbo kbr kca kcb kcc kce kck kcm kcr ke- kea keb kec kee kef kek kem keo ker kfa kfc kff kfm kfo kkb kkc kke kkk kkm kkr kma kmb kmc kme kmf kmk kmm kmo koa kob koc koe kof kok kom koo kor kra krc krf krk kro krr m-f m-o m-r maa mab mac mae maf mak mam mao mar mba mbb mbc mbe mbf mbk mbm mbo mbr mc- mca mcb mcc mce mcf mck mcm mco mcr mea meb mec mee mef mek mem meo mer mfa mfb mfc mfe mff mfm mfo mfr mka mkb mkc mke mkk mkm mko mkr mma mmb mmc mme mmf mmk mmm mmo mmr moa mob moc moe mof mok mom moo mor mra mrb mrc mre mrf mrk mrm mro mrr oaa oab oac oae oaf oak oam oao oar ob- oba obb obc obe obf obk obm obo obr oc- oca ocb occ ocf ock ocm oco ocr oea oeb oec oee oef oem oeo oer of- ofa ofb ofc ofe off ofm ofo ofr oka okb okc oke okk oko okr om- oma omb omc ome omf omm omo omr oo- ooa oob ooc oof ook oom ooo oor or- ora orb orc ore orf ork orm oro orr ra- raa rab rac rae raf rak ram rao rar rba rbb rbc rbe rbf rbk rbm rbo rbr rca rcb rcc rce rcf rcm rco rcr re- rea reb rec ree ref rek rem reo rer rfa rfb rfc rfe rff rfk rfm rfo rfr rkb rkc rke rkf rkk rkm rko rma rmb rmc rme rmf rmm rmo rmr roa rob roc roe rof rok rom roo ror rra rrb rrc rrf rrk rrm rrr