-er a-a a-b a-i a-t aaa aab aae aai aak aar aat ab- aba abb abe abi abk abr abt aea aeb aee aei aek aer aet ai- aia aib aie aii aik air ait aka akb ake aki akk akr ar- ara arb are ari ark arr art at- ata atb ate ati atr att baa bab bae bai bak bar bat bba bbb bbe bbi bbk bbr bbt be- bea beb bee bei bek ber bet bi- bia bib bie bii bik bir bit bka bkb bke bkk bkr bkt bra brb bre bri brk brr brt bta btb bte bti btk btr btt eaa eab eae eai eak ear eat eba ebb ebe ebi ebk ebr ebt eea eeb eee eek eer eet eia eib eie eii eik eir eit eka ekb eke eki ekr ekt era erb ere eri erk err ert eta etb ete eti etk etr ett ia- iaa iab iae iai iar iat iba ibb ibe ibi ibk ibr ibt ie- iea iee iei iek ier iet iia iib iie iii iir iit ika ikb ike iki ikk ikr ikt ir- ira irb ire iri irk irr irt ita itb ite iti itk itt k-t ka- kaa kab kae kai kak kar kat kba kbb kbe kbi kbk kbr ke- kea keb kee kei kek ker ket kia kib kie kii kik kir kit kkb kke kki kkk kkr kkt kra kri krk krr krt kta ktb kte ktk ktr ktt ra- raa rab rae rai rak rar rat rba rbb rbe rbi rbk rbr rbt re- rea reb ree rei rek rer ret ria rib rie rii rik rir rit rkb rke rkk rkt rra rrb rri rrk rrr rrt rta rtb rte rti rtk rtr rtt taa tab tae tai tak tar tat tba tbb tbe tbi tbk tbr tbt te- tea teb tee tei tek ter tet tia tib tie tii tik tir tit tka tkb tke tkk tkr tkt tra trb tre tri trk trr trt tta ttb tte tti ttk ttr ttt