-er a-a a-b aaa aab aae aak aan aap aar ab- aba abb abe abk abn abp abr aea aeb aee aek aen aep aer aka akb ake akk akn akp akr an- ana anb ane ank ann anp anr ap- apa apb ape apk apn app apr ar- ara arb are ark arn arp arr b-p baa bab bae bak ban bap bar bba bbb bbe bbk bbn bbp bbr be- bea beb bee bek ben bep ber bka bkb bke bkk bkn bkp bkr bna bnb bne bnk bnn bnp bnr bpa bpb bpe bpn bpp bpr bra brb bre brk brn brp brr eaa eab eae eak ean eap ear eba ebb ebe ebk ebn ebp ebr eea eeb eee eek een eep eer eka ekb eke ekp ekr en- ena enb ene enk enn enp enr ep- epa epb epe epn epp epr era erb ere erk ern erp err ka- kaa kab kae kak kan kap kar kba kbb kbe kbk kbn kbp kbr ke- kea keb kee kek ken kep ker kkb kke kkk kkn kkp kkr kn- kna kne knk knn knp knr kpa kpe kpk kpn kpp kpr kra krk krn krp krr naa nab nae nak nan nap nar nba nbb nbe nbk nbn nbp nbr ne- nea neb nee nek nen nep ner nka nke nkk nkn nkp nkr nna nnb nne nnk nnn nnp npa npb npe npn npp npr nra nrb nre nrk nrn nrp nrr p-p paa pab pae pak pan pap par pba pbb pbe pbk pbn pbp pbr pea peb pee pek pen pep per pka pkb pke pkn pkp pkr pn- pna pnb pne pnk pnn pnp pnr ppa ppb ppe ppk ppn ppp ppr pra prb pre prk prn prp prr ra- raa rab rae rak ran rap rar rba rbb rbe rbk rbn rbp rbr re- rea reb ree rek ren rep rer rkb rke rkk rkp rna rnb rnn rnp rnr rpa rpb rpe rpk rpn rpp rpr rra rrb rrk rrn rrp rrr