-ic bbb bbc bbi bbr bbt bcb bcc bci bcr bct bi- bib bic bii bir bit brb bri brr brt btb btc bti btr btt c-- cbb cbc cbi cbr cbt ccb ccc cci ccr cct ci- cib cic cii cir cit crb crc cri crr crt ctb ctc cti ctr ctt ibb ibc ibi ibr ibt icb icc ici icr ict iib iic iii iir iit ir- irb irc iri irr irt itb itc iti itt rbb rbc rbi rbr rbt rcb rcc rci rcr rct rib ric rii rir rit rrb rrc rri rrr rrt rtb rtc rti rtr rtt tbb tbc tbi tbr tbt tcb tcc tci tcr tct tib tic tii tir tit trb trc tri trr trt ttb ttc tti ttr ttt