a-a a-b a-c a-t aaa aab aac aad aaf aak aao aar aat ab- aba abb abc abd abf abk abo abr abt ac- aca acb acc acd acf ack aco acr act ad- ada adb adc add adf adk ado adr adt af- afa afb afc afd aff afk afo afr aft aka akb akc akd akk ako akr aoa aob aoc aod aof aok aoo aor aot ar- ara arb arc ard arf ark aro arr art at- ata atb atc atd atf ato atr att baa bab bac bad baf bak bao bar bat bba bbb bbc bbd bbf bbk bbo bbr bbt bca bcb bcc bcd bcf bck bco bcr bct bda bdb bdc bdd bdf bdk bdo bdr bdt bfa bfb bfc bfd bff bfo bfr bft bka bkb bkc bkf bkk bko bkr bkt boa bob boc bod bof bok boo bor bot bra brb brd brf brk bro brr brt bta btb btc btd btf btk bto btr btt c-- caa cab cac cad caf cak cao car cat cba cbb cbc cbd cbf cbk cbo cbr cbt cca ccb ccc ccd ccf cck cco ccr cct cda cdb cdc cdd cdf cdk cdo cdr cdt cfa cfb cfc cfd cff cfk cfo cfr cft cka ckb ckc ckd cko ckt co- coa cob coc cod cof cok coo cor cot cra crb crc crd crf crk cro crr crt cta ctb ctc ctd ctf ctk cto ctr ctt daa dab dac dad daf dak dao dar dat dba dbb dbc dbd dbf dbk dbo dbr dbt dca dcb dcc dcd dcf dck dco dcr dct dda ddb ddc ddd ddf ddk ddo ddr ddt dfa dfb dfc dfd dff dfk dfo dfr dft dka dkb dkc dkk dko dkr dkt doa dob doc dod dof dok doo dor dot dra drb drc drd drk dro drr drt dta dtb dtc dtd dtf dtk dto dtr dtt faa fab fac fad faf fak fao far fat fba fbb fbc fbd fbf fbk fbo fbr fbt fca fcb fcc fcd fcf fck fco fcr fct fda fdb fdc fdd fdf fdk fdo fdr fdt ffa ffc ffd fff ffk ffo ffr fft fka fkb fkc fkf fkk fkt foa fob foc fof fok foo for fot fra frb frc frd frf frk fro frr frt fta ftb ftc ftd ftf ftk fto ftr ftt k-t ka- kaa kab kac kad kaf kak kao kar kat kba kbb kbc kbd kbf kbk kbo kbr kca kcb kcc kcd kck kcr kct kda kdb kdc kdf kdk kdo kdr kdt kfa kfc kfd kff kfo kkb kkc kkk kkr kkt koa kob koc kod kof kok koo kor kot kra krc krd krf krk kro krr krt kta ktb ktc ktf ktk kto ktr ktt oaa oab oac oad oaf oak oao oar oat ob- oba obb obc obd obf obk obo obr obt oc- oca ocb occ ocd ocf ock oco ocr oct oda odb odc odd odf odo odr odt of- ofa ofb ofc ofd off ofo ofr oft oka okb okc okd okk oko okr oo- ooa oob ooc ood oof ook ooo oor oot or- ora orb orc ord orf ork oro orr ort ot- ota otb otc otd otf otk oto otr ott ra- raa rab rac rad raf rak rao rar rat rba rbb rbc rbd rbf rbk rbo rbr rbt rca rcb rcc rcd rcf rco rcr rct rda rdb rdc rdd rdf rdo rdr rdt rfa rfb rfc rfd rff rfk rfo rfr rft rkb rkc rkf rkk rko rkt roa rob roc rod rof rok roo ror rot rra rrb rrc rrd rrf rrk rrr rrt rta rtb rtc rtd rtf rtk rto rtr rtt taa tab tac tad taf tak tao tar tat tba tbb tbc tbd tbf tbk tbo tbr tbt tca tcb tcc tcd tcf tck tco tcr tct tda tdb tdc tdd tdf tdk tdo tdr tdt tfa tfb tfc tfd tff tfk tfo tfr tft tka tkb tkc tkk tko tkr tkt to- toa tob toc tod tof tok too tor tot tra trb trc trd trf trk tro trr trt tta ttb ttc ttd ttf ttk tto ttr ttt