-ic bbb bbc bbe bbi bbk bcb bcc bce bci bck be- beb bec bee bei bek bi- bib bic bie bii bik bkb bkc bke bkk c-- cbb cbc cbe cbi cbk ccb ccc cce cci cck ce- ceb cec cee cei cek ci- cib cic cie cii cik ckb ckc cki ebb ebc ebe ebi ebk ec- ecb ecc ece eci eck eeb eec eee eek eib eic eie eii eik ekb ekc eke eki ibb ibc ibe ibi ibk icb icc ice ici ick ie- iec iee iei iek iib iic iie iii ikb ikc ike iki ikk kbb kbc kbe kbi kbk kcb kcc kce kci kck ke- keb kec kee kei kek kib kic kie kii kik kkb kkc kke kki kkk