a-a a-b a-t aaa aab aao aar aas aat aau aax ab- aba abb abo abr abs abt abu abx aoa aob aoo aor aos aot aou aox ar- ara arb aro arr ars art aru arx as- asa asb aso asr ass ast asu asx at- ata atb ato atr ats att atu atx au- aua aub auo aur aus aut aux ax- axa axo axr axs axt axx b-u baa bab bao bar bas bat bau bax bba bbb bbo bbr bbs bbt bbu bbx boa bob boo bor bos bot bou box bra brb bro brr brs brt bru brx bsa bsb bso bsr bss bst bsu bsx bta btb bto btr bts btt btu btx bua bub buo bur bus but buu bux bxb bxo bxx oaa oab oao oar oas oat oau oax ob- oba obb obo obr obs obt obu obx oo- ooa oob ooo oor oos oot oox or- ora orb oro orr ors ort oru orx os- osa osb oso osr oss ost osu osx ot- ota otb oto otr ots ott otu ou- oua ouo our ous out ox- oxa oxb oxo oxt oxx ra- raa rab rao rar ras rat rau rax rba rbb rbo rbr rbs rbt rbu rbx roa rob roo ror ros rot rou rox rra rrb rrr rrs rrt rru rsa rsb rso rsr rss rst rsu rsx rta rtb rto rtr rts rtt rtu rtx rua rub ruo rur rus rut ruu rux rxr rxs saa sab sao sar sas sat sau sax sba sbb sbo sbr sbs sbt sbu sbx soa sob soo sor sos sot sou sox sr- sra srb sro srr srs srt srx ss- ssa ssb sso ssr sss sst ssu ssx sta stb sto str sts stt stu stx sua sub suo sur sus sut suu sux sxs sxt sxu t-x taa tab tao tar tas tat tau tax tba tbb tbo tbr tbs tbt tbu to- toa tob too tor tos tot tou tox tra trb tro trr trs trt tru trx tsa tsb tso tsr tss tst tsu tsx tta ttb tto ttr tts ttt ttu ttx tua tub tuo tur tus tut tuu tux txs txt txu ua- uaa uab uao uar uas uat uau uba ubb ubo ubr ubs ubt ubu ubx uoa uob uoo uor uos uot uox ur- ura urb uro urr urs urt uru urx usa usb uso usr uss ust usu usx uta utb uto utr uts utt utu utx uua uur uus uut uuu uxb uxo uxr uxt uxu xaa xar xas xat xau xbr xbx xoa xoo xor xos xot xox xrt xrx xsa xsb xss xst xtr xts xtx xus xxo xxx