-ic a-a a-b a-c a-i a-t aaa aab aac aai aak aao aas aat ab- aba abb abc abi abk abo abs abt ac- aca acb acc aci ack aco acs act ai- aia aib aic aii aik aio ais ait aka akb akc aki akk ako aks aoa aob aoc aoi aok aoo aos aot as- asa asb asc asi ask aso ass ast at- ata atb atc ati ato ats att baa bab bac bai bak bao bas bat bba bbb bbc bbi bbk bbo bbs bbt bca bcb bcc bci bck bco bcs bct bi- bia bib bic bii bik bio bis bit bka bkb bkc bkk bko bks bkt boa bob boc boi bok boo bos bot bsa bsb bsc bsi bsk bso bss bst bta btb btc bti btk bto bts btt c-- caa cab cac cai cak cao cas cat cba cbb cbc cbi cbk cbo cbs cbt cca ccb ccc cci cck cco ccs cct ci- cia cib cic cii cik cio cis cit cka ckb ckc cki cko cks ckt co- coa cob coc coi cok coo cos cot csa csb csc csi csk cso css cst cta ctb ctc cti ctk cto cts ctt ia- iaa iab iac iai iao ias iat iba ibb ibc ibi ibk ibo ibs ibt ica icb icc ici ick ico ics ict iia iib iic iii iio iis iit ika ikb ikc iki ikk iko iks ikt io- ioa iob ioc ioi ioo ios iot is- isa isb isc isi isk iso iss ist ita itb itc iti itk ito its itt k-t ka- kaa kab kac kai kak kao kas kat kba kbb kbc kbi kbk kbo kbs kca kcb kcc kci kck kcs kct kia kib kic kii kik kio kis kit kkb kkc kki kkk kks kkt koa kob koc koi kok koo kos kot ksa ksb ksc ksi ksk kso kss kst kta ktb ktc ktk kto kts ktt o-i oaa oab oac oai oak oao oas oat ob- oba obb obc obi obk obo obs obt oc- oca ocb occ oci ock oco ocs oct oia oib oic oii oik oio ois oit oka okb okc oki okk oko oks oo- ooa oob ooc ooi ook ooo oos oot os- osa osb osc osi osk oso oss ost ot- ota otb otc oti otk oto ots ott saa sab sac sai sak sao sas sat sba sbb sbc sbi sbk sbo sbs sbt sca scb scc sci sck sco scs sct sia sib sic sii sik sio sis sit sk- ska skb skc ski skk sko sks skt soa sob soc soi sok soo sos sot ss- ssa ssb ssc ssi ssk sso sss sst sta stb stc sti stk sto sts stt taa tab tac tai tak tao tas tat tba tbb tbc tbi tbk tbo tbs tbt tca tcb tcc tci tck tco tcs tct tia tib tic tii tik tio tis tit tka tkb tkc tkk tko tks tkt to- toa tob toc toi tok too tos tot tsa tsb tsc tsi tsk tso tss tst tta ttb ttc tti ttk tto tts ttt