-er b-u bbb bbe bbi bbk bbo bbr bbs bbu be- beb bee bei bek beo ber bes beu bi- bib bie bii bik bio bir bis biu bkb bke bkk bko bkr bks bob boe boi bok boo bor bos bou brb bre bri brk bro brr brs bru bsb bse bsi bsk bso bsr bss bsu bub bue bui buk buo bur bus buu ebb ebe ebi ebk ebo ebr ebs ebu eeb eee eek eeo eer ees eib eie eii eik eio eir eis eiu ekb eke eki eko ekr eks eku eo- eob eoe eoi eok eoo eor eos eou erb ere eri erk ero err ers eru es- esb ese esi esk eso esr ess esu eu- eub eue eui eur eus ibb ibe ibi ibk ibo ibr ibs ibu ie- iee iei iek ier ies iib iie iii iio iir iis iiu ikb ike iki ikk iko ikr iks iku io- iob ioe ioi ioo ior ios iou ir- irb ire iri irk iro irr irs iru is- isb ise isi isk iso isr iss isu iu- iub iue iui iur ius kbb kbe kbi kbk kbo kbr kbs kbu ke- keb kee kei kek keo ker kes kib kie kii kik kio kir kis kiu kkb kke kki kkk kkr kks kku kob koe koi kok koo kor kos kou kri krk kro krr krs kru ksb kse ksi ksk kso ksr kss ksu kub kue kui kuk kur kus kuu o-i ob- obb obe obi obk obo obr obs obu oeb oee oei oeo oer oes oib oie oii oik oio oir ois oiu okb oke oki okk oko okr oks oku oo- oob ooi ook ooo oor oos or- orb ore ori ork oro orr ors oru os- osb ose osi osk oso osr oss osu ou- oue oui ouk ouo our ous rbb rbe rbi rbk rbo rbr rbs rbu re- reb ree rei rek reo rer res reu rib rie rii rik rio rir ris rkb rke rkk rko rks rku rob roe roi rok roo ror ros rou rrb rri rrk rrr rrs rru rsb rse rsi rsk rso rsr rss rsu rub rue rui ruk ruo rur rus ruu sbb sbe sbi sbk sbo sbr sbs sbu se- seb see sei sek seo ser ses seu sib sie sii sik sio sir sis siu sk- skb ske ski skk sko skr sks sku sob soe soi sok soo sor sos sou sr- srb sre sri srk sro srr srs ss- ssb sse ssi ssk sso ssr sss ssu sub sue sui suk suo sur sus suu ubb ube ubi ubk ubo ubr ubs ubu ueb uee uei uer ues uib uie uii uio uir uis uiu ukb uke uki ukk ukr uku uob uoe uok uoo uor uos ur- urb ure uri urk uro urr urs uru usb use usi usk uso usr uss usu uue uur uus uuu