-er -ic bbb bbc bbe bbf bbi bbk bbr bbs bcb bcc bce bcf bci bck bcr bcs be- beb bec bee bef bei bek ber bes bfb bfc bfe bff bfi bfr bfs bi- bib bic bie bif bii bik bir bis bkb bkc bke bkf bkk bkr bks brb bre brf bri brk brr brs bsb bsc bse bsf bsi bsk bsr bss c-- cbb cbc cbe cbf cbi cbk cbr cbs ccb ccc cce ccf cci cck ccr ccs ce- ceb cec cee cef cei cek cer ces cfb cfc cfe cff cfi cfk cfr cfs ci- cib cic cie cif cii cik cir cis ckb ckc cki cks crb crc cre crf cri crk crr crs csb csc cse csf csi csk csr css ebb ebc ebe ebf ebi ebk ebr ebs ec- ecb ecc ece ecf eci eck ecr ecs eeb eec eee eef eek eer ees ef- efb efc efe eff efi efr efs eib eic eie eif eii eik eir eis ekb ekc eke ekf eki ekr eks erb erc ere erf eri erk err ers es- esb esc ese esf esi esk esr ess fbb fbc fbe fbf fbi fbk fbr fbs fcb fcc fce fcf fci fck fcr fcs feb fec fee fef fei fek fer fes ffc ffe fff ffi ffk ffr ffs fib fic fie fif fii fik fir fis fkb fkc fkf fki fkk frb frc fre frf fri frk frr frs fsb fsc fse fsf fsi fsk fsr fss i-f ibb ibc ibe ibf ibi ibk ibr ibs icb icc ice icf ici ick icr ics ie- iec iee ief iei iek ier ies ifb ifc ife iff ifi ifr ifs iib iic iie iif iii iir iis ikb ikc ike ikf iki ikk ikr iks ir- irb irc ire irf iri irk irr irs is- isb isc ise isf isi isk isr iss kbb kbc kbe kbf kbi kbk kbr kbs kcb kcc kce kci kck kcr kcs ke- keb kec kee kef kei kek ker kes kfc kff kfi kfs kib kic kie kif kii kik kir kis kkb kkc kke kki kkk kkr kks krc krf kri krk krr krs ksb ksc kse ksf ksi ksk ksr kss rbb rbc rbe rbf rbi rbk rbr rbs rcb rcc rce rcf rci rcr rcs re- reb rec ree ref rei rek rer res rfb rfc rfe rff rfi rfk rfr rfs rib ric rie rif rii rik rir ris rkb rkc rke rkf rkk rks rrb rrc rrf rri rrk rrr rrs rsb rsc rse rsf rsi rsk rsr rss sbb sbc sbe sbf sbi sbk sbr sbs scb scc sce scf sci sck scr scs se- seb sec see sef sei sek ser ses sfb sfc sfe sff sfi sfk sfr sfs sib sic sie sif sii sik sir sis sk- skb skc ske skf ski skk skr sks sr- srb src sre srf sri srk srr srs ss- ssb ssc sse ssf ssi ssk ssr sss