-ic a-a a-b a-c a-i a-t aaa aab aac aai aak aao aar aat ab- aba abb abc abi abk abo abr abt ac- aca acb acc aci ack aco acr act ai- aia aib aic aii aik aio air ait aka akb akc aki akk ako akr aoa aob aoc aoi aok aoo aor aot ar- ara arb arc ari ark aro arr art at- ata atb atc ati ato atr att baa bab bac bai bak bao bar bat bba bbb bbc bbi bbk bbo bbr bbt bca bcb bcc bci bck bco bcr bct bi- bia bib bic bii bik bio bir bit bka bkb bkc bkk bko bkr bkt boa bob boc boi bok boo bor bot bra brb bri brk bro brr brt bta btb btc bti btk bto btr btt c-- caa cab cac cai cak cao car cat cba cbb cbc cbi cbk cbo cbr cbt cca ccb ccc cci cck cco ccr cct ci- cia cib cic cii cik cio cir cit cka ckb ckc cki cko ckt co- coa cob coc coi cok coo cor cot cra crb crc cri crk cro crr crt cta ctb ctc cti ctk cto ctr ctt ia- iaa iab iac iai iao iar iat iba ibb ibc ibi ibk ibo ibr ibt ica icb icc ici ick ico icr ict iia iib iic iii iio iir iit ika ikb ikc iki ikk iko ikr ikt io- ioa iob ioc ioi ioo ior iot ir- ira irb irc iri irk iro irr irt ita itb itc iti itk ito itt k-t ka- kaa kab kac kai kak kao kar kat kba kbb kbc kbi kbk kbo kbr kca kcb kcc kci kck kcr kct kia kib kic kii kik kio kir kit kkb kkc kki kkk kkr kkt koa kob koc koi kok koo kor kot kra krc kri krk kro krr krt kta ktb ktc ktk kto ktr ktt o-i oaa oab oac oai oak oao oar oat ob- oba obb obc obi obk obo obr obt oc- oca ocb occ oci ock oco ocr oct oia oib oic oii oik oio oir oit oka okb okc oki okk oko okr oo- ooa oob ooc ooi ook ooo oor oot or- ora orb orc ori ork oro orr ort ot- ota otb otc oti otk oto otr ott ra- raa rab rac rai rak rao rar rat rba rbb rbc rbi rbk rbo rbr rbt rca rcb rcc rci rco rcr rct ria rib ric rii rik rio rir rit rkb rkc rkk rko rkt roa rob roc roi rok roo ror rot rra rrb rrc rri rrk rrr rrt rta rtb rtc rti rtk rto rtr rtt taa tab tac tai tak tao tar tat tba tbb tbc tbi tbk tbo tbr tbt tca tcb tcc tci tck tco tcr tct tia tib tic tii tik tio tir tit tka tkb tkc tkk tko tkr tkt to- toa tob toc toi tok too tor tot tra trb trc tri trk tro trr trt tta ttb ttc tti ttk tto ttr ttt