a-a a-b a-i aaa aab aai aam aao aar aas ab- aba abb abi abm abo abr abs ai- aia aib aii aim aio air ais ama amb ami amm amo amr ams aoa aob aoi aom aoo aor aos ar- ara arb ari arm aro arr ars as- asa asb asi asm aso asr ass baa bab bai bam bao bar bas bba bbb bbi bbm bbo bbr bbs bi- bia bib bii bim bio bir bis bma bmb bmi bmm bmo bmr bms boa bob boi bom boo bor bos bra brb bri brm bro brr brs bsa bsb bsi bsm bso bsr bss ia- iaa iab iai iam iao iar ias iba ibb ibi ibm ibo ibr ibs iia iib iii iim iio iir iis im- ima imb imi imm imo ims io- ioa iob ioi iom ioo ior ios ir- ira irb iri irm iro irr irs is- isa isb isi ism iso isr iss m-o m-r maa mab mai mam mao mar mas mba mbb mbi mbm mbo mbr mbs mi- mia mib mii mim mio mir mis mma mmb mmi mmm mmo mmr mms moa mob moi mom moo mor mos mra mrb mri mrm mro mrr mrs msa msb msi msm mso msr mss o-i oaa oab oai oam oao oar oas ob- oba obb obi obm obo obr obs oia oib oii oim oio oir ois om- oma omb omi omm omo omr oms oo- ooa oob ooi oom ooo oor oos or- ora orb ori orm oro orr ors os- osa osb osi osm oso osr oss ra- raa rab rai ram rao rar ras rba rbb rbi rbm rbo rbr rbs ria rib rii rim rio rir ris rma rmb rmi rmm rmo rmr rms roa rob roi rom roo ror ros rra rrb rri rrm rrr rrs rsa rsb rsi rsm rso rsr rss saa sab sai sam sao sar sas sba sbb sbi sbm sbo sbr sbs sia sib sii sim sio sir sis sma smb smi smm smo smr sms soa sob soi som soo sor sos sr- sra srb sri srm sro srr srs ss- ssa ssb ssi ssm sso ssr sss