-er b-u bbb bbc bbe bbk bbn bbo bbr bbt bbu bcb bcc bce bck bcn bco bcr bct bcu be- beb bec bee bek ben beo ber bet beu bkb bkc bke bkk bkn bko bkr bkt bnb bnc bne bnk bnn bno bnr bnt bnu bob boc boe bok bon boo bor bot bou brb bre brk brn bro brr brt bru btb btc bte btk btn bto btr btt btu bub buc bue buk bun buo bur but buu c-- cbb cbc cbe cbk cbn cbo cbr cbt cbu ccb ccc cce cck ccn cco ccr cct ccu ce- ceb cec cee cek cen ceo cer cet ceu ckb ckc cko ckt cn- cnb cnc cne cnn cno cnr cnt cnu co- cob coc coe cok con coo cor cot cou crb crc cre crk crn cro crr crt cru ctb ctc cte ctk ctn cto ctr ctt ctu cub cuc cue cuk cun cuo cur cut cuu ebb ebc ebe ebk ebn ebo ebr ebt ebu ec- ecb ecc ece eck ecn eco ecr ect ecu eeb eec eee eek een eeo eer eet ekb ekc eke eko ekr ekt eku en- enb enc ene enk enn eno enr ent enu eo- eob eoc eoe eok eon eoo eor eot eou erb erc ere erk ern ero err ert eru etb etc ete etk etn eto etr ett etu eu- eub euc eue eun eur eut k-t kbb kbc kbe kbk kbn kbo kbr kbu kcb kcc kce kck kcn kcr kct kcu ke- keb kec kee kek ken keo ker ket kkb kkc kke kkk kkn kkr kkt kku kn- knc kne knk knn kno knr knt knu kob koc koe kok kon koo kor kot kou krc krk krn kro krr krt kru ktb ktc kte ktk ktn kto ktr ktt ktu kub kuc kue kuk kun kur kut kuu nbb nbc nbe nbk nbn nbo nbr nbt nbu ncb ncc nce nck ncn nco ncr nct ncu ne- neb nec nee nek nen neo ner net neu nkc nke nkk nkn nko nkr nkt nku nnb nnc nne nnk nnn nno nnt nnu no- nob noc noe nok non noo nor not nou nrb nrc nre nrk nrn nro nrr nrt nru ntb ntc nte ntk ntn nto ntr ntt ntu nub nuc nue nuk nun nuo nur nut nuu ob- obb obc obe obk obn obo obr obt obu oc- ocb occ ock ocn oco ocr oct ocu oeb oec oee oen oeo oer oet okb okc oke okk oko okr oku on- onb onc one onk onn ono onr ont onu oo- oob ooc ook oon ooo oor oot or- orb orc ore ork orn oro orr ort oru ot- otb otc ote otk otn oto otr ott otu ou- ouc oue ouk oun ouo our out rbb rbc rbe rbk rbn rbo rbr rbt rbu rcb rcc rce rcn rco rcr rct rcu re- reb rec ree rek ren reo rer ret reu rkb rkc rke rkk rko rkt rku rnb rnc rnn rno rnr rnt rnu rob roc roe rok ron roo ror rot rou rrb rrc rrk rrn rrr rrt rru rtb rtc rte rtk rtn rto rtr rtt rtu rub ruc rue ruk run ruo rur rut ruu tbb tbc tbe tbk tbn tbo tbr tbt tbu tcb tcc tce tck tcn tco tcr tct tcu te- teb tec tee tek ten teo ter tet teu tkb tkc tke tkk tko tkr tkt tnb tnc tne tnk tnn tno tnr tnt to- tob toc toe tok ton too tor tot tou trb trc tre trk trn tro trr trt tru ttb ttc tte ttk ttn tto ttr ttt ttu tub tuc tue tuk tun tuo tur tut tuu ubb ubc ube ubk ubn ubo ubr ubt ubu ucb ucc uce uck ucn uco ucr uct ucu ueb uec uee uen uer uet ukb ukc uke ukk ukn ukr uku un- unb unc une unk unn uno unr unt unu uob uoc uoe uok uon uoo uor uot ur- urb urc ure urk urn uro urr urt uru utb utc ute utk utn uto utr utt utu uuc uue uun uur uut uuu