-ic a-a a-b a-c a-i aaa aab aac aai aao aar aas ab- aba abb abc abi abo abr abs ac- aca acb acc aci aco acr acs ai- aia aib aic aii aio air ais aoa aob aoc aoi aoo aor aos ar- ara arb arc ari aro arr ars as- asa asb asc asi aso asr ass baa bab bac bai bao bar bas bba bbb bbc bbi bbo bbr bbs bca bcb bcc bci bco bcr bcs bi- bia bib bic bii bio bir bis boa bob boc boi boo bor bos bra brb bri bro brr brs bsa bsb bsc bsi bso bsr bss c-- caa cab cac cai cao car cas cba cbb cbc cbi cbo cbr cbs cca ccb ccc cci cco ccr ccs ci- cia cib cic cii cio cir cis co- coa cob coc coi coo cor cos cra crb crc cri cro crr crs csa csb csc csi cso csr css ia- iaa iab iac iai iao iar ias iba ibb ibc ibi ibo ibr ibs ica icb icc ici ico icr ics iia iib iic iii iio iir iis io- ioa iob ioc ioi ioo ior ios ir- ira irb irc iri iro irr irs is- isa isb isc isi iso isr iss o-i oaa oab oac oai oao oar oas ob- oba obb obc obi obo obr obs oc- oca ocb occ oci oco ocr ocs oia oib oic oii oio oir ois oo- ooa oob ooc ooi ooo oor oos or- ora orb orc ori oro orr ors os- osa osb osc osi oso osr oss ra- raa rab rac rai rao rar ras rba rbb rbc rbi rbo rbr rbs rca rcb rcc rci rco rcr rcs ria rib ric rii rio rir ris roa rob roc roi roo ror ros rra rrb rrc rri rrr rrs rsa rsb rsc rsi rso rsr rss saa sab sac sai sao sar sas sba sbb sbc sbi sbo sbr sbs sca scb scc sci sco scr scs sia sib sic sii sio sir sis soa sob soc soi soo sor sos sr- sra srb src sri sro srr srs ss- ssa ssb ssc ssi sso ssr sss