-er -up b-p b-u bbb bbe bbn bbp bbr bbu be- beb bee ben bep ber beu bnb bne bnn bnp bnr bnu bpb bpe bpn bpp bpr bpu brb bre brn brp brr bru bub bue bun bup bur buu ebb ebe ebn ebp ebr ebu eeb eee een eep eer en- enb ene enn enp enr enu ep- epb epe epn epp epr epu erb ere ern erp err eru eu- eub eue eun eup eur nbb nbe nbn nbp nbr nbu ne- neb nee nen nep ner neu nnb nne nnn nnp nnu npb npe npn npp npr npu nrb nre nrn nrp nrr nru nub nue nun nup nur nuu p-p pbb pbe pbn pbp pbr pbu peb pee pen pep per peu pn- pnb pne pnn pnp pnr pnu ppb ppe ppn ppp ppr ppu prb pre prn prp prr pru pub pue pun pup pur puu rbb rbe rbn rbp rbr rbu re- reb ree ren rep rer reu rnb rnn rnp rnr rnu rpb rpe rpn rpp rpr rpu rrb rrn rrp rrr rru rub rue run rup rur ruu ubb ube ubn ubp ubr ubu ueb uee uen uep uer un- unb une unn unp unr unu up- upb upe upn upp upr upu ur- urb ure urn urp urr uru uue uun uur uuu