-ic a-a a-b a-c a-i a-t aaa aab aac aai aao aar aas aat ab- aba abb abc abi abo abr abs abt ac- aca acb acc aci aco acr acs act ai- aia aib aic aii aio air ais ait aoa aob aoc aoi aoo aor aos aot ar- ara arb arc ari aro arr ars art as- asa asb asc asi aso asr ass ast at- ata atb atc ati ato atr ats att baa bab bac bai bao bar bas bat bba bbb bbc bbi bbo bbr bbs bbt bca bcb bcc bci bco bcr bcs bct bi- bia bib bic bii bio bir bis bit boa bob boc boi boo bor bos bot bra brb bri bro brr brs brt bsa bsb bsc bsi bso bsr bss bst bta btb btc bti bto btr bts btt c-- caa cab cac cai cao car cas cat cba cbb cbc cbi cbo cbr cbs cbt cca ccb ccc cci cco ccr ccs cct ci- cia cib cic cii cio cir cis cit co- coa cob coc coi coo cor cos cot cra crb crc cri cro crr crs crt csa csb csc csi cso csr css cst cta ctb ctc cti cto ctr cts ctt ia- iaa iab iac iai iao iar ias iat iba ibb ibc ibi ibo ibr ibs ibt ica icb icc ici ico icr ics ict iia iib iic iii iio iir iis iit io- ioa iob ioc ioi ioo ior ios iot ir- ira irb irc iri iro irr irs irt is- isa isb isc isi iso isr iss ist ita itb itc iti ito its itt o-i oaa oab oac oai oao oar oas oat ob- oba obb obc obi obo obr obs obt oc- oca ocb occ oci oco ocr ocs oct oia oib oic oii oio oir ois oit oo- ooa oob ooc ooi ooo oor oos oot or- ora orb orc ori oro orr ors ort os- osa osb osc osi oso osr oss ost ot- ota otb otc oti oto otr ots ott ra- raa rab rac rai rao rar ras rat rba rbb rbc rbi rbo rbr rbs rbt rca rcb rcc rci rco rcr rcs rct ria rib ric rii rio rir ris rit roa rob roc roi roo ror ros rot rra rrb rrc rri rrr rrs rrt rsa rsb rsc rsi rso rsr rss rst rta rtb rtc rti rto rtr rts rtt saa sab sac sai sao sar sas sat sba sbb sbc sbi sbo sbr sbs sbt sca scb scc sci sco scr scs sct sia sib sic sii sio sir sis sit soa sob soc soi soo sor sos sot sr- sra srb src sri sro srr srs srt ss- ssa ssb ssc ssi sso ssr sss sst sta stb stc sti sto str sts stt taa tab tac tai tao tar tas tat tba tbb tbc tbi tbo tbr tbs tbt tca tcb tcc tci tco tcr tcs tct tia tib tic tii tio tir tis tit to- toa tob toc toi too tor tos tot tra trb trc tri tro trr trs trt tsa tsb tsc tsi tso tsr tss tst tta ttb ttc tti tto ttr tts ttt