a-a a-b a-i aaa aab aai aap aax aay ab- aba abb abi abp abx aby ai- aia aib aii aip aix aiy ap- apa apb api app apx apy ax- axa axi axp axx ay- aya ayi ayp ayx b-p baa bab bai bap bax bay bba bbb bbi bbp bbx bby bi- bia bib bii bip bix biy bpa bpb bpi bpp bpx bpy bxb bxi bxx by- bya byi byp ia- iaa iab iai iap iba ibb ibi ibp ibx iby iia iib iii iip iix ipa ipb ipi ipp ipx ipy ixi ixy iya iyy p-p paa pab pai pap pax pay pba pbb pbi pbp pbx pby pia pib pii pip pix ppa ppb ppi ppp ppx py- pya pyb pyx xaa xap xbx xia xii xix xpa xpb xpp xxi xxp xxx xxy xyp xyy yaa yab yai yap yax yay ybi ybp yby yii yip ypa yxa yxy yyb yyy