-er a-a a-b aaa aab aae aar aas aau ab- aba abb abe abr abs abu aea aeb aee aer aes aeu ar- ara arb are arr ars aru as- asa asb ase asr ass asu au- aua aub aue aur aus b-u baa bab bae bar bas bau bba bbb bbe bbr bbs bbu be- bea beb bee ber bes beu bra brb bre brr brs bru bsa bsb bse bsr bss bsu bua bub bue bur bus buu eaa eab eae ear eas eau eba ebb ebe ebr ebs ebu eea eeb eee eer ees era erb ere err ers eru es- esa esb ese esr ess esu eu- eua eub eue eur eus ra- raa rab rae rar ras rau rba rbb rbe rbr rbs rbu re- rea reb ree rer res reu rra rrb rrr rrs rru rsa rsb rse rsr rss rsu rua rub rue rur rus ruu saa sab sae sar sas sau sba sbb sbe sbr sbs sbu se- sea seb see ser ses seu sr- sra srb sre srr srs ss- ssa ssb sse ssr sss ssu sua sub sue sur sus suu ua- uaa uab uae uar uas uau uba ubb ube ubr ubs ubu uea ueb uee uer ues ur- ura urb ure urr urs uru usa usb use usr uss usu uua uue uur uus uuu