-er bbb bbe bbo bbr bbs be- beb bee beo ber bes bez bob boe boo bor bos boz brb bre bro brr brs brz bsb bse bso bsr bss bze bzo bzr bzs bzz ebb ebe ebo ebr ebs eeb eee eeo eer ees eo- eob eoe eoo eor eos erb ere ero err ers erz es- esb ese eso esr ess eze ezo ezr ezs ezz ob- obb obe obo obr obs oeb oee oeo oer oes oo- oob ooo oor oos or- orb ore oro orr ors orz os- osb ose oso osr oss oze ozo ozs ozz rbb rbe rbo rbr rbs re- reb ree reo rer res rez rob roe roo ror ros roz rrb rrr rrs rsb rse rso rsr rss rzb rze rzo sbb sbe sbo sbr sbs se- seb see seo ser ses sez sob soe soo sor sos soz sr- srb sre sro srr srs ss- ssb sse sso ssr sss ssz sze szr zbb zbr zbs zeb zee zeo zer zes zez zo- zob zoe zoo zor zos zro zrs zse zsz zzr zzs zzz