a-a a-b a-i aaa aab aai aar aas aax aay ab- aba abb abi abr abs abx aby ai- aia aib aii air ais aix aiy ar- ara arb ari arr ars arx ary as- asa asb asi asr ass asx asy ax- axa axi axr axs axx ay- aya ayi ayr ays ayx baa bab bai bar bas bax bay bba bbb bbi bbr bbs bbx bby bi- bia bib bii bir bis bix biy bra brb bri brr brs brx bry bsa bsb bsi bsr bss bsx bsy bxb bxi bxx by- bya byi byr bys ia- iaa iab iai iar ias iba ibb ibi ibr ibs ibx iby iia iib iii iir iis iix ir- ira irb iri irr irs irx iry is- isa isb isi isr iss isy ixi ixy iya iyr iys iyy ra- raa rab rai rar ras rax ray rba rbb rbi rbr rbs rbx ria rib rii rir ris rix riy rra rrb rri rrr rrs rsa rsb rsi rsr rss rsx rxr rxs ry- rya ryr rys ryy saa sab sai sar sas sax say sba sbb sbi sbr sbs sbx sby sia sib sii sir sis six sr- sra srb sri srr srs srx sry ss- ssa ssb ssi ssr sss ssx sxi sxs sy- sya syb syi syr sys syx xaa xar xas xbr xbx xia xii xis xix xrx xry xsa xsb xsi xss xxi xxx xxy xyr xyy yaa yab yai yar yas yax yay ybi ybr ybs yby yii yir yis yra yrs ysa ysb ysi ysr yss ysy yxa yxy yyb yys yyy