-ic bbb bbc bbi bbn bbr bbs bbt bcb bcc bci bcn bcr bcs bct bi- bib bic bii bin bir bis bit bnb bnc bni bnn bnr bns bnt brb bri brn brr brs brt bsb bsc bsi bsn bsr bss bst btb btc bti btn btr bts btt c-- cbb cbc cbi cbn cbr cbs cbt ccb ccc cci ccn ccr ccs cct ci- cib cic cii cin cir cis cit cn- cnb cnc cni cnn cnr cns cnt crb crc cri crn crr crs crt csb csc csi csn csr css cst ctb ctc cti ctn ctr cts ctt ibb ibc ibi ibn ibr ibs ibt icb icc ici icn icr ics ict iib iic iii iin iir iis iit in- inb inc ini inn inr ins int ir- irb irc iri irn irr irs irt is- isb isc isi isn isr iss ist itb itc iti itn its itt n-i nbb nbc nbi nbn nbr nbs nbt ncb ncc nci ncn ncr ncs nct nib nic nii nin nir nis nit nnb nnc nni nnn nns nnt nrb nrc nri nrn nrr nrs nrt nsb nsc nsi nsn nsr nss nst ntb ntc nti ntn ntr nts ntt rbb rbc rbi rbn rbr rbs rbt rcb rcc rci rcn rcr rcs rct rib ric rii rin rir ris rit rnb rnc rni rnn rnr rns rnt rrb rrc rri rrn rrr rrs rrt rsb rsc rsi rsn rsr rss rst rtb rtc rti rtn rtr rts rtt sbb sbc sbi sbn sbr sbs sbt scb scc sci scn scr scs sct sib sic sii sin sir sis sit snb snc sni snn snr sns snt sr- srb src sri srn srr srs srt ss- ssb ssc ssi ssn ssr sss sst stb stc sti stn str sts stt tbb tbc tbi tbn tbr tbs tbt tcb tcc tci tcn tcr tcs tct tib tic tii tin tir tis tit tnb tnc tni tnn tnr tns tnt trb trc tri trn trr trs trt tsb tsc tsi tsn tsr tss tst ttb ttc tti ttn ttr tts ttt