biper[8], erbie[7], repie[6],
rebe[6], brei[6], brie[6], peri[5],
bee[5], ber[5], erb[5], reb[5], pie[4], per[4], rep[4], rei[3],
be[4], bi[4], pe[3], pi[3], ee[2], er[2], re[2],
