a-a a-b aaa aab aae aao aap aas aax ab- aba abb abe abo abp abs abx aea aeb aee aeo aep aes aex aoa aob aoe aoo aop aos aox ap- apa apb ape apo app aps apx as- asa asb ase aso asp ass asx ax- axa axe axo axp axs axx b-p baa bab bae bao bap bas bax bba bbb bbe bbo bbp bbs bbx be- bea beb bee beo bep bes bex boa bob boe boo bop bos box bpa bpb bpe bpo bpp bps bpx bsa bsb bse bso bsp bss bsx bxb bxo bxx eaa eab eae eao eap eas eax eba ebb ebe ebo ebp ebs ebx eea eeb eee eeo eep ees eex eo- eoa eob eoe eoo eop eos ep- epa epb epe epo epp eps epx es- esa esb ese eso esp ess esx ex- exa exe exo exp exs exx oaa oab oae oao oap oas oax ob- oba obb obe obo obp obs obx oea oeb oee oeo oep oes oex oo- ooa oob ooo oop oos oox op- opa opb ope opo opp ops opx os- osa osb ose oso osp oss osx ox- oxa oxb oxo oxx p-p paa pab pae pao pap pas pax pba pbb pbe pbo pbp pbs pbx pea peb pee peo pep pes pex poa pob poe poo pop pos pox ppa ppb ppe ppo ppp pps ppx ps- psa psb pse pso psp pss psx pxe pxs saa sab sae sao sap sas sax sba sbb sbe sbo sbp sbs sbx se- sea seb see seo sep ses sex soa sob soe soo sop sos sox spa spb spe spo spp sps spx ss- ssa ssb sse sso ssp sss ssx sxs xaa xap xas xbe xbx xee xep xes xex xoa xoo xop xos xox xpa xpb xpe xpo xpp xps xsa xsb xsp xss xxo xxp xxx