-er b-u bbb bbc bbe bbo bbr bbt bbu bcb bcc bce bco bcr bct bcu be- beb bec bee beo ber bet beu bob boc boe boo bor bot bou brb bre bro brr brt bru btb btc bte bto btr btt btu bub buc bue buo bur but buu c-- cbb cbc cbe cbo cbr cbt cbu ccb ccc cce cco ccr cct ccu ce- ceb cec cee ceo cer cet ceu co- cob coc coe coo cor cot cou crb crc cre cro crr crt cru ctb ctc cte cto ctr ctt ctu cub cuc cue cuo cur cut cuu ebb ebc ebe ebo ebr ebt ebu ec- ecb ecc ece eco ecr ect ecu eeb eec eee eeo eer eet eo- eob eoc eoe eoo eor eot eou erb erc ere ero err ert eru etb etc ete eto etr ett etu eu- eub euc eue eur eut ob- obb obc obe obo obr obt obu oc- ocb occ oco ocr oct ocu oeb oec oee oeo oer oet oo- oob ooc ooo oor oot or- orb orc ore oro orr ort oru ot- otb otc ote oto otr ott otu ou- ouc oue ouo our out rbb rbc rbe rbo rbr rbt rbu rcb rcc rce rco rcr rct rcu re- reb rec ree reo rer ret reu rob roc roe roo ror rot rou rrb rrc rrr rrt rru rtb rtc rte rto rtr rtt rtu rub ruc rue ruo rur rut ruu tbb tbc tbe tbo tbr tbt tbu tcb tcc tce tco tcr tct tcu te- teb tec tee teo ter tet teu to- tob toc toe too tor tot tou trb trc tre tro trr trt tru ttb ttc tte tto ttr ttt ttu tub tuc tue tuo tur tut tuu ubb ubc ube ubo ubr ubt ubu ucb ucc uce uco ucr uct ucu ueb uec uee uer uet uob uoc uoe uoo uor uot ur- urb urc ure uro urr urt uru utb utc ute uto utr utt utu uuc uue uur uut uuu