b-u bbb bbc bbe bbf bbl bbu bcb bcc bce bcf bcl bcu be- beb bec bee bef bel beu bfb bfc bfe bff bfl bfu blb blc ble blf bll blu bub buc bue buf bul buu c-- cbb cbc cbe cbf cbl cbu ccb ccc cce ccf ccl ccu ce- ceb cec cee cef cel ceu cfb cfc cfe cff cfl cfu cl- clb clc cle clf cll clu cub cuc cue cuf cul cuu ebb ebc ebe ebf ebl ebu ec- ecb ecc ece ecf ecl ecu eeb eec eee eef eel ef- efb efc efe eff efl elb elc ele elf ell elu eu- eub euc eue euf eul fbb fbc fbe fbf fbl fbu fcb fcc fce fcf fcl fcu feb fec fee fef fel feu ffc ffe fff ffl ffu flb flc fle flf fll flu fub fue fuf ful fuu lbb lbc lbe lbf lbl lbu lcb lcc lce lcf lcl lcu leb lec lee lef lel leu lfb lfc lfe lff lfl lfu llb llc lle llf lll llu lub luc lue luf lul luu ubb ubc ube ubf ubl ubu ucb ucc uce ucf ucl ucu ueb uec uee uef uel ufc ufe uff ufl ufu ulb ulc ule ulf ull ulu uuc uue uuu