-er bbb bbc bbe bbk bbo bbr bbt bcb bcc bce bcj bck bco bcr bct be- beb bec bee bek beo ber bet bjc bjj bjk bjr bjt bkb bkc bke bkk bko bkr bkt bob boc boe boj bok boo bor bot brb bre brj brk bro brr brt btb btc bte btk bto btr btt c-- c-j cbb cbc cbe cbj cbk cbo cbr cbt ccb ccc cce ccj cck cco ccr cct ce- ceb cec cee cej cek ceo cer cet cjb cjc cjk cjr ckb ckc cko ckt co- cob coc coe coj cok coo cor cot crb crc cre crj crk cro crr crt ctb ctc cte ctk cto ctr ctt ebb ebc ebe ebj ebk ebo ebr ebt ec- ecb ecc ece ecj eck eco ecr ect eeb eec eee eek eeo eer eet ejc ejo ejt ekb ekc eke eko ekr ekt eo- eob eoc eoe eok eoo eor eot erb erc ere erk ero err ert etb etc ete etj etk eto etr ett jbc jbj jbk jbo jbr jbt jcb jcc jce jck jco jcr jct jeb jec jee jej jek jeo jer jet jjb jjc jjj jjk jjr jkb jkk jko jkr jkt job joc joe joj jok joo jor jot jrb jrc jrk jro jrr jrt jtb jtc jte jtk jtr jtt k-t kbb kbc kbe kbk kbo kbr kcb kcc kce kck kcr kct ke- keb kec kee kek keo ker ket kjb kjc kje kjr kkb kkc kke kkk kkr kkt kob koc koe kok koo kor kot krc krk kro krr krt ktb ktc kte ktj ktk kto ktr ktt ob- obb obc obe obj obk obo obr obt oc- ocb occ ocj ock oco ocr oct oeb oec oee oeo oer oet ojb ojc oje ojo okb okc oke okj okk oko okr oo- oob ooc ook ooo oor oot or- orb orc ore ork oro orr ort ot- otb otc ote otk oto otr ott rbb rbc rbe rbk rbo rbr rbt rcb rcc rce rcj rco rcr rct re- reb rec ree rek reo rer ret rjc rjk rjr rkb rkc rke rkk rko rkt rob roc roe roj rok roo ror rot rrb rrc rrk rrr rrt rtb rtc rte rtj rtk rto rtr rtt tbb tbc tbe tbj tbk tbo tbr tbt tcb tcc tce tcj tck tco tcr tct te- teb tec tee tej tek teo ter tet tjc tje tjo tjr tkb tkc tke tkk tko tkr tkt to- tob toc toe toj tok too tor tot trb trc tre trk tro trr trt ttb ttc tte ttk tto ttr ttt