-er bbb bbc bbe bbo bbr bbt bcb bcc bce bco bcr bct bcv be- beb bec bee beo ber bet bev bob boc boe boo bor bot bov brb bre bro brr brt brv btb btc bte bto btr btt btv bvb bvc bve bvo bvr bvt bvv c-- cbb cbc cbe cbo cbr cbt cbv ccb ccc cce cco ccr cct ccv ce- ceb cec cee ceo cer cet cev co- cob coc coe coo cor cot cov crb crc cre cro crr crt crv ctb ctc cte cto ctr ctt ctv cvb cvc cve cvo cvr cvt cvv ebb ebc ebe ebo ebr ebt ebv ec- ecb ecc ece eco ecr ect ecv eeb eec eee eeo eer eet eev eo- eob eoc eoe eoo eor eot erb erc ere ero err ert erv etb etc ete eto etr ett etv evb evc eve evo evr evt evv ob- obb obc obe obo obr obt obv oc- ocb occ oco ocr oct ocv oeb oec oee oeo oer oet oo- oob ooc ooo oor oot oov or- orb orc ore oro orr ort orv ot- otb otc ote oto otr ott otv ov- ovb ovc ove ovo ovv rbb rbc rbe rbo rbr rbt rcb rcc rce rco rcr rct rcv re- reb rec ree reo rer ret rev rob roc roe roo ror rot rov rrb rrc rrr rrt rtb rtc rte rto rtr rtt rtv rvb rvc rve rvo rvr rvt rvv tbb tbc tbe tbo tbr tbt tbv tcb tcc tce tco tcr tct tcv te- teb tec tee teo ter tet tev to- tob toc toe too tor tot tov trb trc tre tro trr trt trv ttb ttc tte tto ttr ttt ttv tvb tvc tve tvo tvr tvt v-e vbc vbo vbr vbv vcc vce vco vcr vct veb vec vee veo ver vet vob voc voe voo vor vot vov vrb vrc vre vrr vrt vtb vtc vte vto vtr vtt vtv vvb vvc vvo vvr vvt vvv