-ic a-a a-b a-c a-i a-t aaa aab aac aai aas aat ab- aba abb abc abi abs abt ac- aca acb acc aci acs act ai- aia aib aic aii ais ait as- asa asb asc asi ass ast at- ata atb atc ati ats att baa bab bac bai bas bat bba bbb bbc bbi bbs bbt bca bcb bcc bci bcs bct bi- bia bib bic bii bis bit bsa bsb bsc bsi bss bst bta btb btc bti bts btt c-- caa cab cac cai cas cat cba cbb cbc cbi cbs cbt cca ccb ccc cci ccs cct ci- cia cib cic cii cis cit csa csb csc csi css cst cta ctb ctc cti cts ctt ia- iaa iab iac iai ias iat iba ibb ibc ibi ibs ibt ica icb icc ici ics ict iia iib iic iii iis iit is- isa isb isc isi iss ist ita itb itc iti its itt saa sab sac sai sas sat sba sbb sbc sbi sbs sbt sca scb scc sci scs sct sia sib sic sii sis sit ss- ssa ssb ssc ssi sss sst sta stb stc sti sts stt taa tab tac tai tas tat tba tbb tbc tbi tbs tbt tca tcb tcc tci tcs tct tia tib tic tii tis tit tsa tsb tsc tsi tss tst tta ttb ttc tti tts ttt