-er -ic b-u bbb bbc bbe bbi bbo bbr bbs bbu bcb bcc bce bci bco bcr bcs bcu be- beb bec bee bei beo ber bes beu bi- bib bic bie bii bio bir bis biu bob boc boe boi boo bor bos bou brb bre bri bro brr brs bru bsb bsc bse bsi bso bsr bss bsu bub buc bue bui buo bur bus buu c-- cbb cbc cbe cbi cbo cbr cbs cbu ccb ccc cce cci cco ccr ccs ccu ce- ceb cec cee cei ceo cer ces ceu ci- cib cic cie cii cio cir cis ciu co- cob coc coe coi coo cor cos cou crb crc cre cri cro crr crs cru csb csc cse csi cso csr css csu cub cuc cue cui cuo cur cus cuu ebb ebc ebe ebi ebo ebr ebs ebu ec- ecb ecc ece eci eco ecr ecs ecu eeb eec eee eeo eer ees eib eic eie eii eio eir eis eiu eo- eob eoc eoe eoi eoo eor eos eou erb erc ere eri ero err ers eru es- esb esc ese esi eso esr ess esu eu- eub euc eue eui eur eus ibb ibc ibe ibi ibo ibr ibs ibu icb icc ice ici ico icr ics icu ie- iec iee iei ier ies iib iic iie iii iio iir iis iiu io- iob ioc ioe ioi ioo ior ios iou ir- irb irc ire iri iro irr irs iru is- isb isc ise isi iso isr iss isu iu- iub iuc iue iui iur ius o-i ob- obb obc obe obi obo obr obs obu oc- ocb occ oci oco ocr ocs ocu oeb oec oee oei oeo oer oes oib oic oie oii oio oir ois oiu oo- oob ooc ooi ooo oor oos or- orb orc ore ori oro orr ors oru os- osb osc ose osi oso osr oss osu ou- ouc oue oui ouo our ous rbb rbc rbe rbi rbo rbr rbs rbu rcb rcc rce rci rco rcr rcs rcu re- reb rec ree rei reo rer res reu rib ric rie rii rio rir ris rob roc roe roi roo ror ros rou rrb rrc rri rrr rrs rru rsb rsc rse rsi rso rsr rss rsu rub ruc rue rui ruo rur rus ruu sbb sbc sbe sbi sbo sbr sbs sbu scb scc sce sci sco scr scs scu se- seb sec see sei seo ser ses seu sib sic sie sii sio sir sis siu sob soc soe soi soo sor sos sou sr- srb src sre sri sro srr srs ss- ssb ssc sse ssi sso ssr sss ssu sub suc sue sui suo sur sus suu ubb ubc ube ubi ubo ubr ubs ubu ucb ucc uce uci uco ucr ucs ucu ueb uec uee uei uer ues uib uic uie uii uio uir uis uiu uob uoc uoe uoo uor uos ur- urb urc ure uri uro urr urs uru usb usc use usi uso usr uss usu uuc uue uur uus uuu