-er -ic bbb bbc bbe bbi bbr bbt bcb bcc bce bci bcr bct be- beb bec bee bei ber bet bi- bib bic bie bii bir bit brb bre bri brr brt btb btc bte bti btr btt c-- cbb cbc cbe cbi cbr cbt ccb ccc cce cci ccr cct ce- ceb cec cee cei cer cet ci- cib cic cie cii cir cit crb crc cre cri crr crt ctb ctc cte cti ctr ctt ebb ebc ebe ebi ebr ebt ec- ecb ecc ece eci ecr ect eeb eec eee eer eet eib eic eie eii eir eit erb erc ere eri err ert etb etc ete eti etr ett ibb ibc ibe ibi ibr ibt icb icc ice ici icr ict ie- iec iee iei ier iet iib iic iie iii iir iit ir- irb irc ire iri irr irt itb itc ite iti itt rbb rbc rbe rbi rbr rbt rcb rcc rce rci rcr rct re- reb rec ree rei rer ret rib ric rie rii rir rit rrb rrc rri rrr rrt rtb rtc rte rti rtr rtt tbb tbc tbe tbi tbr tbt tcb tcc tce tci tcr tct te- teb tec tee tei ter tet tib tic tie tii tir tit trb trc tre tri trr trt ttb ttc tte tti ttr ttt