-er bbb bbe bbg bbk bbr bbs be- beb bee beg bek ber bes bgb bge bgg bgk bgr bgs bkb bke bkg bkk bkr bks brb bre brg brk brr brs bsb bse bsg bsk bsr bss ebb ebe ebg ebk ebr ebs eeb eee eeg eek eer ees egb ege egg egr egs ekb eke ekg ekr eks erb ere erg erk err ers es- esb ese esg esk esr ess gbe gbg gbk gbr gbs ge- geb gee geg gek ger ges ggb ggg ggr ggs gkb gks grb gre grg grk grr grs gsb gse gsg gsk gsr gss kbb kbe kbk kbr kbs ke- keb kee keg kek ker kes kgb kgs kkb kke kkk kkr kks krg krk krr krs ksb kse ksg ksk ksr kss rbb rbe rbg rbk rbr rbs re- reb ree reg rek rer res rgb rge rgg rgk rgr rgs rkb rke rkg rkk rks rrb rrg rrk rrr rrs rsb rse rsg rsk rsr rss sbb sbe sbg sbk sbr sbs se- seb see seg sek ser ses sgb sge sgg sgk sgr sgs sk- skb ske skg skk skr sks sr- srb sre srg srk srr srs ss- ssb sse ssg ssk ssr sss