a-a a-t aaa aaf aao aar aas aat aax af- afa aff afo afr afs aft afx aoa aof aoo aor aos aot aox ar- ara arf aro arr ars art arx as- asa asf aso asr ass ast asx at- ata atf ato atr ats att atx ax- axa axo axr axs axt axx faa faf fao far fas fat fax ffa fff ffo ffr ffs fft ffx foa fof foo for fos fot fox fra frf fro frr frs frt fsa fsf fso fsr fss fst fsx fta ftf fto ftr fts ftt ftx fxr fxs fxt fxx oaa oaf oao oar oas oat oax of- ofa off ofo ofr ofs oft ofx oo- ooa oof ooo oor oos oot oox or- ora orf oro orr ors ort orx os- osa osf oso osr oss ost osx ot- ota otf oto otr ots ott ox- oxa oxf oxo oxt oxx ra- raa raf rao rar ras rat rax rfa rff rfo rfr rfs rft roa rof roo ror ros rot rox rra rrf rrr rrs rrt rsa rsf rso rsr rss rst rsx rta rtf rto rtr rts rtt rtx rxr rxs saa saf sao sar sas sat sax sfa sff sfo sfr sfs sft sfx soa sof soo sor sos sot sox sr- sra srf sro srr srs srt srx ss- ssa ssf sso ssr sss sst ssx sta stf sto str sts stt stx sxs sxt t-x taa taf tao tar tas tat tax tfa tff tfo tfr tfs tft tfx to- toa tof too tor tos tot tox tra trf tro trr trs trt trx tsa tsf tso tsr tss tst tsx tta ttf tto ttr tts ttt ttx txf txs txt xaa xaf xar xas xat xfa xfs xft xfx xoa xof xoo xor xos xot xox xrf xrt xrx xsa xss xst xtf xtr xts xtx xxo xxx