-er bbb bbe bbo bbq bbr bbt be- beb bee beo beq ber bet bob boe boo boq bor bot bqe bqt brb bre bro brq brr brt btb bte bto btq btr btt ebb ebe ebo ebq ebr ebt eeb eee eeo eer eet eo- eob eoe eoo eoq eor eot eqe eqq eqt erb ere ero erq err ert etb ete eto etr ett ob- obb obe obo obr obt oeb oee oeo oer oet oo- oob ooo oor oot oqb oqo or- orb ore oro orr ort ot- otb ote oto otr ott qbe qbq qee qeo qet qoo qor qqq qrb qre qrt qto qtq qtr rbb rbe rbo rbr rbt re- reb ree reo req rer ret rob roe roo ror rot rrb rrq rrr rrt rtb rte rto rtq rtr rtt tbb tbe tbo tbr tbt te- teb tee teo teq ter tet to- tob toe too toq tor tot tqo trb tre tro trq trr trt ttb tte tto ttr ttt