-er b-u bbb bbe bbi bbk bbl bbr bbs bbu be- beb bee bei bek bel ber bes beu bi- bib bie bii bik bil bir bis biu bkb bke bkk bkl bkr bks blb ble bli blk bll blr bls blu brb bre bri brk brl brr brs bru bsb bse bsi bsk bsl bsr bss bsu bub bue bui buk bul bur bus buu ebb ebe ebi ebk ebl ebr ebs ebu eeb eee eek eel eer ees eib eie eii eik eil eir eis eiu ekb eke eki ekl ekr eks eku elb ele eli elk ell elr els elu erb ere eri erk erl err ers eru es- esb ese esi esk esl esr ess esu eu- eub eue eui eul eur eus ibb ibe ibi ibk ibl ibr ibs ibu ie- iee iei iek iel ier ies iib iie iii iil iir iis iiu ikb ike iki ikk ikl ikr iks iku il- ilb ile ili ilk ill ilr ils ilu ir- irb ire iri irk irl irr irs iru is- isb ise isi isk isl isr iss isu iu- iub iue iui iur ius kbb kbe kbi kbk kbl kbr kbs kbu ke- keb kee kei kek kel ker kes kib kie kii kik kil kir kis kiu kkb kke kki kkk kkl kkr kks kku kl- klb kli klr kls klu kri krk krl krr krs kru ksb kse ksi ksk ksl ksr kss ksu kub kue kui kuk kul kur kus kuu lbb lbe lbi lbk lbl lbr lbs lbu leb lee lei lek lel ler les leu lib lie lii lik lil lir lis liu lkb lkl lkr lks llb lle lli llk lll llr lls llu lrb lri lrk lrr lrs lru lsb lse lsi lsk lsl lsr lss lsu lub lue lui luk lul lur lus luu rbb rbe rbi rbk rbl rbr rbs rbu re- reb ree rei rek rel rer res reu rib rie rii rik ril rir ris rkb rke rkk rks rku rle rli rll rlr rls rlu rrb rri rrk rrl rrr rrs rru rsb rse rsi rsk rsl rsr rss rsu rub rue rui ruk rur rus ruu sbb sbe sbi sbk sbl sbr sbs sbu se- seb see sei sek sel ser ses seu sib sie sii sik sil sir sis siu sk- skb ske ski skk skl skr sks sku slb sle sli slk sll slr sls slu sr- srb sre sri srk srl srr srs ss- ssb sse ssi ssk ssl ssr sss ssu sub sue sui suk sul sur sus suu ubb ube ubi ubk ubl ubr ubs ubu ueb uee uei uel uer ues uib uie uii uil uir uis uiu ukb uke uki ukk ukl ukr uku ulb ule uli ulk ull ulr uls ulu ur- urb ure uri urk url urr urs uru usb use usi usk usl usr uss usu uue uur uus uuu