-er a-a a-b aaa aab aad aae aar aau aax ab- aba abb abd abe abr abu abx ad- ada adb add ade adr adu adx aea aeb aed aee aer aeu aex ar- ara arb ard are arr aru arx au- aua aub aud aue aur aux ax- axa axe axr axx b-u baa bab bad bae bar bau bax bba bbb bbd bbe bbr bbu bbx bda bdb bdd bde bdr bdu bdx be- bea beb bed bee ber beu bex bra brb brd bre brr bru brx bua bub bud bue bur buu bux bxb bxd bxx daa dab dad dae dar dau dax dba dbb dbd dbe dbr dbu dbx dda ddb ddd dde ddr ddu ddx de- dea deb ded dee der deu dex dra drb drd dre drr dru drx dua dub dud due dur dux dxd dxr dxx eaa eab ead eae ear eau eax eba ebb ebd ebe ebr ebu ebx ed- eda edb edd ede edr edu edx eea eeb eed eee eer eex era erb erd ere err eru eu- eua eub eud eue eur eux ex- exa exd exe exr exu exx ra- raa rab rad rae rar rau rax rba rbb rbd rbe rbr rbu rbx rda rdb rdd rde rdr rdu rdx re- rea reb red ree rer reu rex rra rrb rrd rrr rru rua rub rud rue rur ruu rux rxr ua- uaa uab uad uae uar uau uba ubb ube ubr ubu ubx uda udb udd ude udr udu udx uea ueb ued uee uer ur- ura urb urd ure urr uru urx uua uue uur uuu uxb uxr uxu xaa xad xar xau xbe xbr xbx xda xdb xde xdr xed xee xer xeu xex xrd xrx xue xxx