-er a-a a-b aaa aab aae aam aan aao aap aar ab- aba abb abe abm abn abo abp abr aea aeb aee aem aen aeo aep aer ama amb ame amm amn amo amp amr an- ana anb ane anm ann ano anp anr aoa aob aoe aom aon aoo aop aor ap- apa apb ape apm apn apo app apr ar- ara arb are arm arn aro arp arr b-p baa bab bae bam ban bao bap bar bba bbb bbe bbm bbn bbo bbp bbr be- bea beb bee bem ben beo bep ber bma bmb bme bmm bmn bmo bmp bmr bna bnb bne bnn bno bnp bnr boa bob boe bom bon boo bop bor bpa bpb bpe bpm bpn bpo bpp bpr bra brb bre brm brn bro brp brr eaa eab eae eam ean eao eap ear eba ebb ebe ebm ebn ebo ebp ebr eea eeb eee eem een eeo eep eer em- ema emb eme emm emn emo emp emr en- ena enb ene enm enn eno enp enr eo- eoa eob eoe eom eon eoo eop eor ep- epa epb epe epm epn epo epp epr era erb ere erm ern ero erp err m-o m-r maa mab mae mam man mao map mar mba mbb mbe mbm mbo mbp mbr mea meb mee mem men meo mep mer mma mmb mme mmm mmn mmo mmp mmr mna mnb mne mnm mnn mno mnp mnr moa mob moe mom mon moo mop mor mpa mpb mpe mpm mpn mpo mpp mpr mra mrb mre mrm mrn mro mrp mrr naa nab nae nam nan nao nap nar nba nbb nbe nbm nbn nbo nbp nbr ne- nea neb nee nem nen neo nep ner nma nmb nme nmm nmn nmo nmp nmr nna nnb nne nnm nnn nno nnp no- noa nob noe nom non noo nop nor npa npb npe npm npn npo npp npr nra nrb nre nrm nrn nro nrp nrr oaa oab oae oam oan oao oap oar ob- oba obb obe obm obn obo obp obr oea oeb oee oem oen oeo oep oer om- oma omb ome omm omn omo omp omr on- ona onb one onn ono onp onr oo- ooa oob oom oon ooo oop oor op- opa opb ope opm opn opo opp opr or- ora orb ore orm orn oro orp orr p-p paa pab pae pam pan pao pap par pba pbb pbe pbm pbn pbo pbp pbr pea peb pee pem pen peo pep per pma pmb pme pmm pmn pmo pmp pmr pn- pna pnb pne pnm pnn pno pnp pnr poa pob poe pom pon poo pop por ppa ppb ppe ppm ppn ppo ppp ppr pra prb pre prm prn pro prp prr ra- raa rab rae ram ran rao rap rar rba rbb rbe rbm rbn rbo rbp rbr re- rea reb ree rem ren reo rep rer rma rmb rme rmm rmn rmo rmp rmr rna rnb rnm rnn rno rnp rnr roa rob roe rom ron roo rop ror rpa rpb rpe rpm rpn rpo rpp rpr rra rrb rrm rrn rrp rrr