a-a a-b a-i a-z aaa aab aai aao aap aax aaz ab- aba abb abi abo abp abx abz ai- aia aib aii aio aip aix aiz aoa aob aoi aoo aop aox ap- apa apb api apo app apx ax- axa axi axo axp axx az- aza azb azi azo azp azx azz b-p baa bab bai bao bap bax baz bba bbb bbi bbo bbp bbx bi- bia bib bii bio bip bix biz boa bob boi boo bop box boz bpa bpb bpi bpo bpp bpx bxb bxi bxo bxx bza bzo bzp bzz ia- iaa iab iai iao iap iaz iba ibb ibi ibo ibp ibx ibz iia iib iii iio iip iix io- ioa iob ioi ioo iop ipa ipb ipi ipo ipp ipx ixi iza izi izo izz o-i oaa oab oai oao oap oax ob- oba obb obi obo obp obx oia oib oii oio oip oiz oo- ooa oob ooi ooo oop oox op- opa opb opi opo opp opx ox- oxa oxb oxi oxo oxx oza ozo ozz p-p paa pab pai pao pap pax paz pba pbb pbi pbo pbp pbx pbz pia pib pii pio pip pix piz poa pob poi poo pop pox poz ppa ppb ppi ppo ppp ppx ppz pzp xaa xap xbx xia xii xio xix xoa xoi xoo xop xox xpa xpb xpo xpp xxi xxo xxp xxx zaa zab zai zao zap zax zaz zbb zia zib zio zip zix ziz zo- zoa zob zoi zoo zox zpi zpo zpp zxx zzx zzz