b-u bbb bbc bbd bbe bbk bbo bbu bcb bcc bcd bce bck bco bcu bdb bdc bdd bde bdk bdo bdu be- beb bec bed bee bek beo beu bkb bkc bke bkk bko bob boc bod boe bok boo bou bub buc bud bue buk buo buu c-- cbb cbc cbd cbe cbk cbo cbu ccb ccc ccd cce cck cco ccu cdb cdc cdd cde cdk cdo cdu ce- ceb cec ced cee cek ceo ceu ckb ckc ckd cko co- cob coc cod coe cok coo cou cub cuc cud cue cuk cuo cuu dbb dbc dbd dbe dbk dbo dbu dcb dcc dcd dce dck dco dcu ddb ddc ddd dde ddk ddo ddu de- deb dec ded dee dek deo deu dkb dkc dke dkk dko dku dob doc dod doe dok doo dou dub duc dud due duk duo ebb ebc ebd ebe ebk ebo ebu ec- ecb ecc ecd ece eck eco ecu ed- edb edc edd ede edk edo edu eeb eec eed eee eek eeo ekb ekc ekd eke eko eku eo- eob eoc eod eoe eok eoo eou eu- eub euc eud eue kbb kbc kbd kbe kbk kbo kbu kcb kcc kcd kce kck kcu kdb kdc kde kdk kdo kdu ke- keb kec ked kee kek keo kkb kkc kke kkk kku kob koc kod koe kok koo kou kub kuc kud kue kuk kuu ob- obb obc obd obe obk obo obu oc- ocb occ ocd ock oco ocu odb odc odd ode odo odu oeb oec oed oee oeo okb okc okd oke okk oko oku oo- oob ooc ood ook ooo ou- ouc oud oue ouk ouo ubb ubc ube ubk ubo ubu ucb ucc ucd uce uck uco ucu udb udc udd ude udk udo udu ueb uec ued uee ukb ukc uke ukk uku uob uoc uod uoe uok uoo uuc uue uuu