-er -ic b-u bbb bbc bbe bbi bbk bbr bbt bbu bcb bcc bce bci bck bcr bct bcu be- beb bec bee bei bek ber bet beu bi- bib bic bie bii bik bir bit biu bkb bkc bke bkk bkr bkt brb bre bri brk brr brt bru btb btc bte bti btk btr btt btu bub buc bue bui buk bur but buu c-- cbb cbc cbe cbi cbk cbr cbt cbu ccb ccc cce cci cck ccr cct ccu ce- ceb cec cee cei cek cer cet ceu ci- cib cic cie cii cik cir cit ciu ckb ckc cki ckt crb crc cre cri crk crr crt cru ctb ctc cte cti ctk ctr ctt ctu cub cuc cue cui cuk cur cut cuu ebb ebc ebe ebi ebk ebr ebt ebu ec- ecb ecc ece eci eck ecr ect ecu eeb eec eee eek eer eet eib eic eie eii eik eir eit eiu ekb ekc eke eki ekr ekt eku erb erc ere eri erk err ert eru etb etc ete eti etk etr ett etu eu- eub euc eue eui eur eut ibb ibc ibe ibi ibk ibr ibt ibu icb icc ice ici ick icr ict icu ie- iec iee iei iek ier iet iib iic iie iii iir iit iiu ikb ikc ike iki ikk ikr ikt iku ir- irb irc ire iri irk irr irt iru itb itc ite iti itk itt itu iu- iub iuc iue iui iur iut k-t kbb kbc kbe kbi kbk kbr kbu kcb kcc kce kci kck kcr kct kcu ke- keb kec kee kei kek ker ket kib kic kie kii kik kir kit kiu kkb kkc kke kki kkk kkr kkt kku krc kri krk krr krt kru ktb ktc kte ktk ktr ktt ktu kub kuc kue kui kuk kur kut kuu rbb rbc rbe rbi rbk rbr rbt rbu rcb rcc rce rci rcr rct rcu re- reb rec ree rei rek rer ret reu rib ric rie rii rik rir rit rkb rkc rke rkk rkt rku rrb rrc rri rrk rrr rrt rru rtb rtc rte rti rtk rtr rtt rtu rub ruc rue rui ruk rur rut ruu tbb tbc tbe tbi tbk tbr tbt tbu tcb tcc tce tci tck tcr tct tcu te- teb tec tee tei tek ter tet teu tib tic tie tii tik tir tit tiu tkb tkc tke tkk tkr tkt trb trc tre tri trk trr trt tru ttb ttc tte tti ttk ttr ttt ttu tub tuc tue tui tuk tur tut tuu ubb ubc ube ubi ubk ubr ubt ubu ucb ucc uce uci uck ucr uct ucu ueb uec uee uei uer uet uib uic uie uii uir uit uiu ukb ukc uke uki ukk ukr uku ur- urb urc ure uri urk urr urt uru utb utc ute uti utk utr utt utu uuc uue uur uut uuu