-er a-a a-b a-i aaa aab aae aai aan aao aap aar ab- aba abb abe abi abn abo abp abr aea aeb aee aei aen aeo aep aer ai- aia aib aie aii ain aio aip air an- ana anb ane ani ann ano anp anr aoa aob aoe aoi aon aoo aop aor ap- apa apb ape api apn apo app apr ar- ara arb are ari arn aro arp arr b-p baa bab bae bai ban bao bap bar bba bbb bbe bbi bbn bbo bbp bbr be- bea beb bee bei ben beo bep ber bi- bia bib bie bii bin bio bip bir bna bnb bne bni bnn bno bnp bnr boa bob boe boi bon boo bop bor bpa bpb bpe bpi bpn bpo bpp bpr bra brb bre bri brn bro brp brr eaa eab eae eai ean eao eap ear eba ebb ebe ebi ebn ebo ebp ebr eea eeb eee een eeo eep eer eia eib eie eii ein eio eip eir en- ena enb ene eni enn eno enp enr eo- eoa eob eoe eoi eon eoo eop eor ep- epa epb epe epi epn epo epp epr era erb ere eri ern ero erp err ia- iaa iab iae iai ian iao iap iar iba ibb ibe ibi ibn ibo ibp ibr ie- iea iee iei ien iep ier iia iib iie iii iin iio iip iir in- ina inb ine ini inn ino inp inr io- ioa iob ioe ioi ion ioo iop ior ipa ipb ipe ipi ipn ipo ipp ipr ir- ira irb ire iri irn iro irp irr n-i naa nab nae nai nan nao nap nar nba nbb nbe nbi nbn nbo nbp nbr ne- nea neb nee nei nen neo nep ner nia nib nie nii nin nio nip nir nna nnb nne nni nnn nno nnp no- noa nob noe noi non noo nop nor npa npb npe npi npn npo npp npr nra nrb nre nri nrn nro nrp nrr o-i oaa oab oae oai oan oao oap oar ob- oba obb obe obi obn obo obp obr oea oeb oee oei oen oeo oep oer oia oib oie oii oin oio oip oir on- ona onb one oni onn ono onp onr oo- ooa oob ooi oon ooo oop oor op- opa opb ope opi opn opo opp opr or- ora orb ore ori orn oro orp orr p-p paa pab pae pai pan pao pap par pba pbb pbe pbi pbn pbo pbp pbr pea peb pee pei pen peo pep per pia pib pie pii pin pio pip pir pn- pna pnb pne pni pnn pno pnp pnr poa pob poe poi pon poo pop por ppa ppb ppe ppi ppn ppo ppp ppr pra prb pre pri prn pro prp prr ra- raa rab rae rai ran rao rap rar rba rbb rbe rbi rbn rbo rbp rbr re- rea reb ree rei ren reo rep rer ria rib rie rii rin rio rip rir rna rnb rni rnn rno rnp rnr roa rob roe roi ron roo rop ror rpa rpb rpe rpi rpn rpo rpp rpr rra rrb rri rrn rrp rrr