-er b-u bbb bbc bbe bbf bbl bbr bbu bcb bcc bce bcf bcl bcr bcu be- beb bec bee bef bel ber beu bfb bfc bfe bff bfl bfr bfu blb blc ble blf bll blr blu brb bre brf brl brr bru bub buc bue buf bul bur buu c-- cbb cbc cbe cbf cbl cbr cbu ccb ccc cce ccf ccl ccr ccu ce- ceb cec cee cef cel cer ceu cfb cfc cfe cff cfl cfr cfu cl- clb clc cle clf cll clr clu crb crc cre crf crl crr cru cub cuc cue cuf cul cur cuu ebb ebc ebe ebf ebl ebr ebu ec- ecb ecc ece ecf ecl ecr ecu eeb eec eee eef eel eer ef- efb efc efe eff efl efr elb elc ele elf ell elr elu erb erc ere erf erl err eru eu- eub euc eue euf eul eur fbb fbc fbe fbf fbl fbr fbu fcb fcc fce fcf fcl fcr fcu feb fec fee fef fel fer feu ffc ffe fff ffl ffr ffu flb flc fle flf fll flr flu frb frc fre frf frl frr fru fub fue fuf ful fur fuu lbb lbc lbe lbf lbl lbr lbu lcb lcc lce lcf lcl lcr lcu leb lec lee lef lel ler leu lfb lfc lfe lff lfl lfr lfu llb llc lle llf lll llr llu lrb lrc lrf lrr lru lub luc lue luf lul lur luu rbb rbc rbe rbf rbl rbr rbu rcb rcc rce rcf rcl rcr rcu re- reb rec ree ref rel rer reu rfb rfc rfe rff rfl rfr rfu rlc rle rlf rll rlr rlu rrb rrc rrf rrl rrr rru rub ruc rue ruf rur ruu ubb ubc ube ubf ubl ubr ubu ucb ucc uce ucf ucl ucr ucu ueb uec uee uef uel uer ufc ufe uff ufl ufr ufu ulb ulc ule ulf ull ulr ulu ur- urb urc ure urf url urr uru uuc uue uur uuu