b-u bbb bbc bbd bbo bbs bbt bbu bcb bcc bcd bco bcs bct bcu bdb bdc bdd bdo bds bdt bdu bob boc bod boo bos bot bou bsb bsc bsd bso bss bst bsu btb btc btd bto bts btt btu bub buc bud buo bus but buu c-- cbb cbc cbd cbo cbs cbt cbu ccb ccc ccd cco ccs cct ccu cdb cdc cdd cdo cds cdt cdu co- cob coc cod coo cos cot cou csb csc csd cso css cst csu ctb ctc ctd cto cts ctt ctu cub cuc cud cuo cus cut cuu dbb dbc dbd dbo dbs dbt dbu dcb dcc dcd dco dcs dct dcu ddb ddc ddd ddo dds ddt ddu dob doc dod doo dos dot dou dsb dsc dsd dso dss dst dsu dtb dtc dtd dto dts dtt dtu dub duc dud duo dus dut ob- obb obc obd obo obs obt obu oc- ocb occ ocd oco ocs oct ocu odb odc odd odo ods odt odu oo- oob ooc ood ooo oos oot os- osb osc osd oso oss ost osu ot- otb otc otd oto ots ott otu ou- ouc oud ouo ous out sbb sbc sbd sbo sbs sbt sbu scb scc scd sco scs sct scu sdb sdc sdd sdo sds sdt sdu sob soc sod soo sos sot sou ss- ssb ssc ssd sso sss sst ssu stb stc std sto sts stt stu sub suc sud suo sus sut suu tbb tbc tbd tbo tbs tbt tbu tcb tcc tcd tco tcs tct tcu tdb tdc tdd tdo tds tdt tdu to- tob toc tod too tos tot tou tsb tsc tsd tso tss tst tsu ttb ttc ttd tto tts ttt ttu tub tuc tud tuo tus tut tuu ubb ubc ubo ubs ubt ubu ucb ucc ucd uco ucs uct ucu udb udc udd udo uds udt udu uob uoc uod uoo uos uot usb usc usd uso uss ust usu utb utc utd uto uts utt utu uuc uus uut uuu