bbb bbc bbl bbn bbt bcb bcc bcl bcn bct blb blc bll bln blt bnb bnc bnl bnn bnt btb btc btl btn btt c-- cbb cbc cbl cbn cbt ccb ccc ccl ccn cct cl- clb clc cll cln clt cn- cnb cnc cnl cnn cnt ctb ctc ctl ctn ctt lbb lbc lbl lbt lcb lcc lcl lcn lct llb llc lll lln llt lnb lnc lnl lnn lnt ltb ltc ltl ltt nbb nbc nbl nbn nbt ncb ncc ncl ncn nct nlb nlc nll nln nlt nnb nnc nnl nnn nnt ntb ntc ntn ntt tbb tbc tbl tbn tbt tcb tcc tcl tcn tct tlc tll tln tlt tnb tnc tnl tnn tnt ttb ttc ttl ttn ttt