-ic bbb bbc bbd bbi bbo bbt bcb bcc bcd bci bco bct bdb bdc bdd bdi bdo bdt bi- bib bic bid bii bio bit bob boc bod boi boo bot btb btc btd bti bto btt c-- cbb cbc cbd cbi cbo cbt ccb ccc ccd cci cco cct cdb cdc cdd cdi cdo cdt ci- cib cic cid cii cio cit co- cob coc cod coi coo cot ctb ctc ctd cti cto ctt dbb dbc dbd dbi dbo dbt dcb dcc dcd dci dco dct ddb ddc ddd ddi ddo ddt di- dib dic did dii dio dit dob doc dod doi doo dot dtb dtc dtd dti dto dtt i-d ibb ibc ibd ibi ibo ibt icb icc icd ici ico ict idb idc idd idi ido idt iib iic iid iii iio iit io- iob ioc iod ioi ioo iot itb itc itd iti ito itt o-i ob- obb obc obd obi obo obt oc- ocb occ ocd oci oco oct odb odc odd odi odo odt oib oic oid oii oio oit oo- oob ooc ood ooi ooo oot ot- otb otc otd oti oto ott tbb tbc tbd tbi tbo tbt tcb tcc tcd tci tco tct tdb tdc tdd tdi tdo tdt tib tic tid tii tio tit to- tob toc tod toi too tot ttb ttc ttd tti tto ttt