-er a-a a-b a-c a-t aaa aab aac aae aak aar aat aav ab- aba abb abc abe abk abr abt abv ac- aca acb acc ace ack acr act acv aea aeb aec aee aek aer aet aev aka akb akc ake akk akr akv ar- ara arb arc are ark arr art arv at- ata atb atc ate atr att atv av- ava avb avc ave avk avr avt baa bab bac bae bak bar bat bav bba bbb bbc bbe bbk bbr bbt bca bcb bcc bce bck bcr bct bcv be- bea beb bec bee bek ber bet bev bka bkb bkc bke bkk bkr bkt bkv bra brb bre brk brr brt brv bta btb btc bte btk btr btt btv bva bvb bvc bve bvk bvr bvt bvv c-- caa cab cac cae cak car cat cav cba cbb cbc cbe cbk cbr cbt cbv cca ccb ccc cce cck ccr cct ccv ce- cea ceb cec cee cek cer cet cev cka ckb ckc ckt cra crb crc cre crk crr crt crv cta ctb ctc cte ctk ctr ctt ctv cva cvb cvc cve cvk cvr cvt cvv eaa eab eac eae eak ear eat eav eba ebb ebc ebe ebk ebr ebt ebv ec- eca ecb ecc ece eck ecr ect ecv eea eeb eec eee eek eer eet eev eka ekb ekc eke ekr ekt ekv era erb erc ere erk err ert erv eta etb etc ete etk etr ett etv eva evb evc eve evr evt evv k-t ka- kaa kab kac kae kak kar kat kav kba kbb kbc kbe kbk kbr kca kcb kcc kce kck kcr kct ke- kea keb kec kee kek ker ket kev kkb kkc kke kkk kkr kkt kkv kra krc krk krr krt krv kta ktb ktc kte ktk ktr ktt ktv kva kvb kvk kvr kvv ra- raa rab rac rae rak rar rat rav rba rbb rbc rbe rbk rbr rbt rca rcb rcc rce rcr rct rcv re- rea reb rec ree rek rer ret rev rkb rkc rke rkk rkt rkv rra rrb rrc rrk rrr rrt rta rtb rtc rte rtk rtr rtt rtv rva rvb rvc rve rvr rvt rvv taa tab tac tae tak tar tat tav tba tbb tbc tbe tbk tbr tbt tbv tca tcb tcc tce tck tcr tct tcv te- tea teb tec tee tek ter tet tev tka tkb tkc tke tkk tkr tkt tra trb trc tre trk trr trt trv tta ttb ttc tte ttk ttr ttt ttv tva tvb tvc tve tvk tvr tvt v-a v-e vaa vab vac vae vak var vat vav vba vbc vbk vbr vbv vca vcc vce vcr vct vea veb vec vee vek ver vet vka vkb vkt vra vrb vrc vre vrk vrr vrt vta vtb vtc vte vtk vtr vtt vtv vva vvb vvc vvr vvt vvv