-er bbb bbe bbi bbr bbs be- beb bee bei ber bes bi- bib bie bii bir bis brb bre bri brr brs bsb bse bsi bsr bss ebb ebe ebi ebr ebs eeb eee eer ees eib eie eii eir eis erb ere eri err ers es- esb ese esi esr ess ibb ibe ibi ibr ibs ie- iee iei ier ies iib iie iii iir iis ir- irb ire iri irr irs is- isb ise isi isr iss rbb rbe rbi rbr rbs re- reb ree rei rer res rib rie rii rir ris rrb rri rrr rrs rsb rse rsi rsr rss sbb sbe sbi sbr sbs se- seb see sei ser ses sib sie sii sir sis sr- srb sre sri srr srs ss- ssb sse ssi ssr sss