-er b-u bbb bbc bbe bbk bbo bbr bbs bbt bbu bbx bcb bcc bce bck bco bcr bcs bct bcu bcx be- beb bec bee bek beo ber bes bet beu bex bkb bkc bke bkk bko bkr bks bkt bkx bob boc boe bok boo bor bos bot bou box brb bre brk bro brr brs brt bru brx bsb bsc bse bsk bso bsr bss bst bsu bsx btb btc bte btk bto btr bts btt btu btx bub buc bue buk buo bur bus but buu bux bxb bxo bxx c-- cbb cbc cbe cbk cbo cbr cbs cbt cbu cbx ccb ccc cce cck cco ccr ccs cct ccu ccx ce- ceb cec cee cek ceo cer ces cet ceu cex ckb ckc cko cks ckt ckx co- cob coc coe cok coo cor cos cot cou cox crb crc cre crk cro crr crs crt cru crx csb csc cse csk cso csr css cst csu csx ctb ctc cte ctk cto ctr cts ctt ctu ctx cub cuc cue cuk cuo cur cus cut cuu cxc cxk cxo cxr cxs cxt cxx ebb ebc ebe ebk ebo ebr ebs ebt ebu ebx ec- ecb ecc ece eck eco ecr ecs ect ecu ecx eeb eec eee eek eeo eer ees eet eex ekb ekc eke eko ekr eks ekt eku eo- eob eoc eoe eok eoo eor eos eot eou erb erc ere erk ero err ers ert eru es- esb esc ese esk eso esr ess est esu esx etb etc ete etk eto etr ets ett etu etx eu- eub euc eue eur eus eut eux ex- exc exe exo exr exs ext exu exx k-t kbb kbc kbe kbk kbo kbr kbs kbu kbx kcb kcc kce kck kcr kcs kct kcu kcx ke- keb kec kee kek keo ker kes ket kex kkb kkc kke kkk kkr kks kkt kku kob koc koe kok koo kor kos kot kou krc krk kro krr krs krt kru ksb ksc kse ksk kso ksr kss kst ksu ktb ktc kte ktk kto ktr kts ktt ktu kub kuc kue kuk kur kus kut kuu kxo ob- obb obc obe obk obo obr obs obt obu obx oc- ocb occ ock oco ocr ocs oct ocu ocx oeb oec oee oeo oer oes oet oex okb okc oke okk oko okr oks oku oo- oob ooc ook ooo oor oos oot oox or- orb orc ore ork oro orr ors ort oru orx os- osb osc ose osk oso osr oss ost osu osx ot- otb otc ote otk oto otr ots ott otu ou- ouc oue ouk ouo our ous out ox- oxb oxc oxo oxt oxx rbb rbc rbe rbk rbo rbr rbs rbt rbu rbx rcb rcc rce rco rcr rcs rct rcu rcx re- reb rec ree rek reo rer res ret reu rex rkb rkc rke rkk rko rks rkt rku rob roc roe rok roo ror ros rot rou rox rrb rrc rrk rrr rrs rrt rru rsb rsc rse rsk rso rsr rss rst rsu rsx rtb rtc rte rtk rto rtr rts rtt rtu rtx rub ruc rue ruk ruo rur rus rut ruu rux rxr rxs sbb sbc sbe sbk sbo sbr sbs sbt sbu sbx scb scc sce sck sco scr scs sct scu scx se- seb sec see sek seo ser ses set seu sex sk- skb skc ske skk sko skr sks skt sku skx sob soc soe sok soo sor sos sot sou sox sr- srb src sre srk sro srr srs srt srx ss- ssb ssc sse ssk sso ssr sss sst ssu ssx stb stc ste stk sto str sts stt stu stx sub suc sue suk suo sur sus sut suu sux sxc sxs sxt sxu t-x tbb tbc tbe tbk tbo tbr tbs tbt tbu tcb tcc tce tck tco tcr tcs tct tcu tcx te- teb tec tee tek teo ter tes tet teu tex tkb tkc tke tkk tko tkr tks tkt to- tob toc toe tok too tor tos tot tou tox trb trc tre trk tro trr trs trt tru trx tsb tsc tse tsk tso tsr tss tst tsu tsx ttb ttc tte ttk tto ttr tts ttt ttu ttx tub tuc tue tuk tuo tur tus tut tuu tux txe txk txs txt txu ubb ubc ube ubk ubo ubr ubs ubt ubu ubx ucb ucc uce uck uco ucr ucs uct ucu ueb uec uee uer ues uet ukb ukc uke ukk ukr uku uob uoc uoe uok uoo uor uos uot uox ur- urb urc ure urk uro urr urs urt uru urx usb usc use usk uso usr uss ust usu usx utb utc ute utk uto utr uts utt utu utx uuc uue uur uus uut uuu uxb uxc uxo uxr uxt uxu xbc xbe xbr xbx xcb xcr xcx xee xer xes xet xeu xex xkb xke xks xoc xok xoo xor xos xot xox xrc xrt xrx xsb xsc xss xst xtc xtr xts xtx xue xus xxo xxx