-er bbb bbc bbe bbg bbk bbr bbt bcb bcc bce bcg bck bcr bct be- beb bec bee beg bek ber bet bgb bgc bge bgg bgk bgr bgt bkb bkc bke bkg bkk bkr bkt brb bre brg brk brr brt btb btc bte btg btk btr btt c-- cbb cbc cbe cbg cbk cbr cbt ccb ccc cce ccg cck ccr cct ce- ceb cec cee ceg cek cer cet cgb cgc cge cgg cgr cgt ckb ckc ckt crb crc cre crg crk crr crt ctb ctc cte ctg ctk ctr ctt ebb ebc ebe ebg ebk ebr ebt ec- ecb ecc ece ecg eck ecr ect eeb eec eee eeg eek eer eet egb egc ege egg egr egt ekb ekc eke ekg ekr ekt erb erc ere erg erk err ert etb etc ete etg etk etr ett gbc gbe gbg gbk gbr gbt gcb gcc gce gcg gck gcr gct ge- geb gec gee geg gek ger get ggb ggc ggg ggr ggt gkb gkt grb grc gre grg grk grr grt gtb gtc gte gtg gtk gtr gtt k-t kbb kbc kbe kbk kbr kcb kcc kce kcg kck kcr kct ke- keb kec kee keg kek ker ket kgb kgc kkb kkc kke kkk kkr kkt krc krg krk krr krt ktb ktc kte ktg ktk ktr ktt rbb rbc rbe rbg rbk rbr rbt rcb rcc rce rcg rcr rct re- reb rec ree reg rek rer ret rgb rgc rge rgg rgk rgr rgt rkb rkc rke rkg rkk rkt rrb rrc rrg rrk rrr rrt rtb rtc rte rtg rtk rtr rtt tbb tbc tbe tbg tbk tbr tbt tcb tcc tce tcg tck tcr tct te- teb tec tee teg tek ter tet tgb tgc tge tgg tgk tgr tgt tkb tkc tke tkg tkk tkr tkt trb trc tre trg trk trr trt ttb ttc tte ttg ttk ttr ttt