a-a a-b a-q aaa aab aaq aar aas ab- aba abb abq abr abs aqa aqr aqs ar- ara arb arq arr ars as- asa asb asq asr ass baa bab baq bar bas bba bbb bbq bbr bbs bra brb brq brr brs bsa bsb bsr bss qaa qar qas qba qbq qbs qqq qra qrb qrs qsa qsr ra- raa rab raq rar ras rba rbb rbr rbs rqs rra rrb rrq rrr rrs rsa rsb rsq rsr rss saa sab saq sar sas sba sbb sbq sbr sbs sqa sqq sqr sqs sr- sra srb srq srr srs ss- ssa ssb ssq ssr sss